                    FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

CENTER FOR BIO-ETHICAL REFORM,           
INC.; GREGG CUNNINGHAM,
               Plaintiffs-Appellants,
                 v.                             No. 04-17496
CITY AND COUNTY OF HONOLULU;                      D.C. No.
PETER CARLISLE, in his official
capacity as the City and County of           CV-03-00154-DAE
                                               ORDER AND
Honolulu Prosecuting Attorney;
                                                AMENDED
BOISSE P. CORREA, in his official
                                                 OPINION
capacity as Chief of Police,
Honolulu Police Department,
successor to Lee D. Donohue,
              Defendants-Appellees.
                                         
        Appeal from the United States District Court
                 for the District of Hawaii
         David A. Ezra, District Judge, Presiding

                 Argued and Submitted
           November 21, 2005—Honolulu, Hawaii

                      Filed May 23, 2006
                     Amended July 6, 2006

   Before: Myron H. Bright,* M. Margaret McKeown, and
            Richard R. Clifton, Circuit Judges.

                  Opinion by Judge McKeown

   *The Honorable Myron H. Bright, Senior United States Circuit Judge
for the Eighth Circuit, sitting by designation.

                               7423
          CENTER FOR BIO-ETHICAL REFORM v. HONOLULU          7427


                          COUNSEL

Robert J. Muise, Thomas More Law Center, Ann Arbor,
Michigan, and Robert K. Matsumoto, Honolulu, Hawaii, for
the appellants.

Carrie K.S. Okinaga, Corporation Counsel, Gordon D. Nel-
son, Deputy Corporation Counsel, and Jon M. Van Dyke,
Special Deputy Corporation Counsel, Honolulu, Hawaii, for
the appellees.


                            ORDER

  The Opinion filed on May 23, 2006, is amended as follows:

   On slip Opinion page 5645, line 10 of footnote 1, insert the
following text before the sentence that begins with “We note
that Hawaii Revised Statute . . .”: Neither did the district court
abuse its discretion in denying the Center’s request to amend
its complaint. See Flowers v. First Hawaiian Bank, 295 F.3d
7428     CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
966, 976 (9th Cir. 2002) (“We review for abuse of discretion
the denial of leave to amend after a responsive pleading has
been filed.”).

   On slip Opinion page 5646, line 32, beginning with the sen-
tence “In Skysign we explained . . .” and ending on page 5647,
line 4, with “Id. at 1115.”, delete and replace with the follow-
ing text: In Skysign, we explained that “advertising is an area
traditionally subject to regulation under the states’ police
power, and we therefore presume that federal law does not
displace Honolulu’s regulatory authority over advertising
absent a clear statement of the federal intent to do so, either
by Congress or by the FAA as Congress’s delegate. . . . How-
ever, no such presumption applies to section 40-6.1, the aerial
signage ordinance, which rather than addressing advertising
generally specifically targets for regulation ‘an area where
there has been a history of significant federal presence,’ i.e.,
navigable airspace.” Id. at 1115-16 (citations omitted).

   On slip Opinion page 5649, at the end of footnote 3, insert
the following text: Consideration of these documents and
after-enacted changes is best left to the district court, not to
the court of appeals for initial analysis. There is good reason
why we generally do not consider issues for the first time on
appeal—the record has not been developed, the district court
has not had an opportunity to consider the issue, and the par-
ties’ arguments are not developed against the district court
decision.

  With these amendments, the panel has voted to deny the
petition for panel rehearing. Judges McKeown and Clifton
vote to deny the petition for rehearing en banc and Judge
Bright so recommends. The full court has been advised of the
petition for rehearing and rehearing en banc and no judge has
requested a vote on whether to rehear the matter en banc. See
Fed. R. App. P. 35. The petition for panel rehearing and the
petition for rehearing en banc are denied.
         CENTER FOR BIO-ETHICAL REFORM v. HONOLULU        7429
                         OPINION

McKEOWN, Circuit Judge:

   The City and County of Honolulu, Hawaii (“Honolulu”),
has a long history of comprehensive regulatory oversight over
its visual landscape, an effort designed to protect the area’s
unique and widely-renowned scenic resources. For example,
in 1957, Honolulu was among the first municipalities to enact
a comprehensive ordinance regulating signs, see State v. Dia-
mond Motors, Inc., 429 P.2d 825, 826 (Haw. 1967), and, in
1978, Honolulu first passed what later became Revised Ordi-
nance of Honolulu § 40-6.1 (1996) (“the Ordinance”), which
prohibits aerial advertising.

   The question presented in this appeal is whether the Ordi-
nance may be used to restrict an advocacy group from towing
aerial banners over the beaches of Honolulu. To answer this
question, we must first decide whether the Ordinance is pre-
empted by federal law, and, if not, whether it passes constitu-
tional scrutiny under the First Amendment and the Equal
Protection Clause of the Fourteenth Amendment. Less than
five years ago, we answered the preemption question in the
negative. Skysign Int’l, Inc. v. City and County of Honolulu,
276 F.3d 1109 (9th Cir. 2002). Nothing presented in this
appeal persuades us that we should depart from that prece-
dent. As to the constitutional question, we hold that the Ordi-
nance passes constitutional muster. The Ordinance is a
reasonable and viewpoint neutral restriction on speech in a
nonpublic forum, and the banner towing prohibited by the
Ordinance is neither a historically important form of commu-
nication nor speech that has unique identifying attributes for
which there is no practical substitute. We affirm the district
court’s grant of summary judgment in favor of Honolulu.

                        BACKGROUND

   Honolulu’s aerial advertising Ordinance is part of a long-
standing scheme aimed at regulating outdoor advertising in
7430      CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
order to protect the critical visual landscape that has made the
area famous. The linkage between the scenic viewscapes and
the economic well-being of Honolulu, including its tourist
industry, is not disputed. As one witness aptly stated, “looking
out to sea from Waikiki Beach without commercial or promo-
tional interruption is as crucial to the Hawaii visitor’s and res-
ident’s experience as is the uninterrupted viewing of the
canyon for travelers to the Grand Canyon. . . . [F]ew things
can damage the distinctive character of a scenic view faster
than a large moving sign pulled through the center of the field
of vision.”

  Given the importance of preserving the area’s coastal and
scenic visual beauty, and in an effort to prevent potentially
dangerous aerial distractions for its coastal vehicle traffic,
Honolulu enacted the Ordinance, which, with few exceptions,
prohibits aerial advertising:

    (a) Except as allowed under subsection (b), no per-
    son shall use any type of aircraft or other self-
    propelled or buoyant airborne object to display in
    any manner or for any purpose whatsoever any sign
    or advertising device. For the purpose of this section,
    a “sign or advertising device” includes, but is not
    limited to, a poster, banner, writing, picture, paint-
    ing, light, model, display, emblem, notice, illustra-
    tion, insignia, symbol or any other form of
    advertising sign or device.

    (b)   Exceptions.

       (1) Subsection (a) shall not prohibit the display
    of an identifying mark, trade name, trade insignia, or
    trademark on the exterior of an aircraft or self-
    propelled or buoyant airborne object if the displayed
    item is under the ownership or registration of the air-
    craft’s or airborne object’s owner.
         CENTER FOR BIO-ETHICAL REFORM v. HONOLULU             7431
       (2) Subsection (a) shall not prohibit the display
    of a sign or advertising device placed wholly and
    visible only within the interior of an aircraft or self-
    propelled or buoyant airborne object.

       (3) Subsection (a) shall not apply to the display
    of a sign or advertising device when placed on or
    attached to any ground, building, or structure and
    subject to regulation under Chapter 21 or 41. Such
    a sign or advertising device shall be permitted, pro-
    hibited, or otherwise regulated as provided under the
    applicable chapter.

Section 40-6.1.

   The Center for Bio-Ethical Reform and its director Gregg
Cunningham (collectively “the Center”) challenge the Ordi-
nance because it prevents the Center from carrying out its
aerial advocacy campaign over Honolulu’s beaches. The Cen-
ter is a pro-life/anti-abortion advocacy group that hires air-
planes to tow aerial banners over heavily populated areas.
These banners are typically 100-feet-long and display graphic
photographs of aborted fetuses. The Center has used this pub-
licity technique in many states and has found it to be very
effective in spreading its message.

   Absent specific authorization, Federal Aviation Adminis-
tration (“FAA”) regulations prohibit operation of civilian air-
craft over densely populated areas. 14 C.F.R. § 91.313(e).
Consequently, prior to towing its banners, the Center obtained
permission from the FAA in the form of a Certificate of
Authorization (“Certificate”). The Certificate states that it
authorizes “aerial advertisement banner towing,” but contains
a note stating that it “does not constitute a waiver of any State
law or local ordinance.” The Certificate grants authorization
to tow banners in “the contiguous United States of America,
Alaska, Hawaii, and Puerto Rico.”
7432       CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
   Upset that under the Ordinance it could not tow banners
over Honolulu, the Center filed suit seeking declaratory and
injunctive relief to prevent enforcement of the Ordinance. The
Center alleged that the Ordinance violates its right to free
speech under the First Amendment and its right to Equal Pro-
tection under the Fourteenth Amendment and that federal law
preempts the Ordinance. The district court denied the Center’s
motion for preliminary injunction and we affirmed that ruling.
Center for Bio-Ethical Reform, Inc. v. City and County of
Honolulu, 84 F.App’x 779, 2003 WL 23096041 (9th Cir.
2003).

  The Center and Honolulu then filed cross-motions for sum-
mary judgment and the district court granted summary judg-
ment in favor of Honolulu. Center for Bio-Ethical Reform,
Inc. v. City and County of Honolulu, 345 F. Supp. 2d 1123 (D.
Haw. 2004).1 The district court rejected the preemption argu-
ment and held that the Ordinance did not violate the Center’s
constitutional rights.
  1
    The Center also claimed that Honolulu did not have jurisdiction to
enforce the Ordinance above coastal waters outside the territorial bounda-
ries of Honolulu. Because the Center’s original complaint did not include
any reference to this claim, the district court declined to address it. Center
for Bio-Ethical Reform, 345 F. Supp. 2d at 1138-39. We likewise do not
consider the merits of this claim because it does not fall within the “nar-
row and discretionary exceptions to the general rule against considering
issues for the first time on appeal.” Alaska v. United States, 201 F.3d
1154, 1163 (9th Cir. 2000) (quoting Jovanovich v. United States, 813 F.2d
1035, 1037 (9th Cir. 1987)). Neither did the district court abuse its discre-
tion in denying the Center’s request to amend its complaint. See Flowers
v. First Hawaiian Bank, 295 F.3d 966, 976 (9th Cir. 2002) (“We review
for abuse of discretion the denial of leave to amend after a responsive
pleading has been filed. We note that Hawaii Revised Statute § 445-113
(2005) was recently amended to allow a county to regulate “outdoor
advertising devices located in the airspace or waters beyond the bounda-
ries of the county that are visible from any public highway, park, or other
public place located within the county.”
          CENTER FOR BIO-ETHICAL REFORM v. HONOLULU           7433
                           ANALYSIS

I.   THE ORDINANCE IS NOT PREEMPTED BY FEDERAL LAW

   [1] Within certain Constitutional limits and absent explicit
language preempting state law, Congress may implicitly pre-
empt state law through a comprehensive regulatory scheme
that occupies the entire field being regulated, leaving no room
for state or local supplementation:

     Absent explicit preemptive language, Congress’
     intent to supercede state law altogether may be found
     from a scheme of federal regulation so pervasive as
     to make reasonable the inference that Congress left
     no room for the States to supplement it, because the
     Act of Congress may touch a field in which the fed-
     eral interest is so dominant that the federal system
     will be assumed to preclude enforcement of state
     laws on the same subject, or because the object
     sought to be obtained by the federal law and the
     character of obligations imposed by it may reveal the
     same purpose.

Pac. Gas & Elec. Co. v. State Energy Res. Conserv. & Dev.
Comm’n, 461 U.S. 190, 203-04 (1983) (quotation marks omit-
ted); see also Barber v. Hawaii, 42 F.3d 1185, 1189 (9th Cir.
1994). This form of preemption is known as field preemption.
Federal law may also preempt state law where state law is dis-
placed in favor of an actual conflict with federal law. This
form of preemption is known as conflict preemption:

     Even where Congress has not entirely displaced state
     regulation in a specific area, state law is pre-empted
     to the extent that it actually conflicts with federal
     law. Such a conflict arises when compliance with
     both federal and state regulations is a physical
     impossibility, or where state law stands as an obsta-
7434      CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
    cle to the accomplishment and execution of the full
    purposes and objectives of Congress.

Pac. Gas & Elec., 461 U.S. at 204 (quotation marks and cita-
tions omitted); see also Barber, 42 F.3d at 1189.

   [2] The Center argues that Congress, via the FAA, occupies
the entire field of tow banner regulation, and further, that the
FAA Certificate impermissibly conflicts with the Ordinance.
The Ninth Circuit has already spoken on this issue, upholding
the Ordinance against a virtually identical federal preemption
challenge. Skysign, 276 F.3d 1109. In Skysign, we explained
that “advertising is an area traditionally subject to regulation
under the states’ police power, and we therefore presume that
federal law does not displace Honolulu’s regulatory authority
over advertising absent a clear statement of the federal intent
to do so, either by Congress or by the FAA as Congress’s del-
egate. . . . However, no such presumption applies to section
40-6.1, the aerial signage ordinance, which rather than
addressing advertising generally specifically targets for regu-
lation ‘an area where there has been a history of significant
federal presence,’ i.e., navigable airspace.” Id. at 1115-16
(citations omitted). Neither Congress nor the FAA has “ex-
erted its statutory authority to a degree that warrants a holding
that it has preempted the entire field.” Id. at 1116. Although
Congress has “left open the door for the FAA to do so through
the use of its authority to develop regulations for the use of
navigable airspace. . . . without some affirmative accompany-
ing indication, [the FAA regulatory scheme does not] compel
a conclusion that the agency has sought to occupy the field to
the full.” Id.

   [3] We also analyzed whether a FAA “certificate of waiv-
er,” which is similar to the Certificate in this appeal, precludes
the enforcement of the Ordinance under principles of conflict
preemption. Id. at 1117. If the federal law “contemplates
coexistence between federal and local regulatory schemes,”
conflict preemption does not come into play. Id. The certifi-
           CENTER FOR BIO-ETHICAL REFORM v. HONOLULU                    7435
cate of waiver in Skysign contemplated such a coexistence, as
evidenced by a specific provision that provided: “[t]he [air-
craft] operator, by exercising the privilege of this waiver,
understands all local laws and ordinances relating to aerial
signs, and accepts responsibility for all actions and conse-
quences associated with such operations.” Id. at 1117-18. The
FAA Handbook, which is the same one analyzed in Skysign
and in this appeal, suggests including “similar provisions in
waivers for banner tow operations . . . that the certificate and
its special provisions ‘do not supersede any local, state, or city
ordinance(s) prohibiting aerial advertising.’ ” Id. at 1118. The
Center’s Certificate contains precisely such a provision, stat-
ing that the Certificate “does not constitute a waiver of any
State law or local ordinance.”

   In the face of compelling precedent to the contrary, the
Center urges that Skysign is no longer controlling because
after the case was decided, the FAA issued a notice on Octo-
ber 7, 2002, that proposed deletion of certain provisions of the
FAA Handbook. FAA Notice N 8700.16. We give the notice
no weight because it self-expired on October 7, 2003, without
any change to the FAA Handbook. See US West, Inc. v.
United States, 48 F.3d 1092, 1101 (9th Cir. 1994) (stating that
“ ‘failed legislative proposals’ and [accompanying] recom-
mendations in committee reports . . . . [are not] sufficient evi-
dence to suggest that there is any relevant congressional intent
to which this court could defer.”), judgment vacated on other
grounds, 516 U.S. 1155 (1996). Thus, the substance of the
proposed change in the FAA Handbook merits no review on
our part. For the same reason, we have no occasion to analyze
a letter from the FAA’s Deputy Chief Counsel explaining the
proposed changes.2
   2
     The FAA’s position on banner towing is difficult to divine. It is fair to
say that its view covers the waterfront, or in this case, the airspace. In an
amicus brief filed in Skysign, the agency took the position that federal law
did not preempt local sign ordinances. See Skysign, 276 F.3d at 1117. In
other opinion letters, the FAA took the opposite view. See id. at 1117 &
1118 n.6 (discussing various letters from FAA counsel and Banner Adver.,
Inc. v. City of Boulder, 868 P.2d 1077 (Colo. 1994)). And, to confuse mat-
ters further, the FAA letter offered in connection with the October 7, 2002
notice contains internally conflicting language.
7436       CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
   [4] Because the FAA Handbook and regulations before us
remain the same as they were in Skysign and the Center’s Cer-
tificate contemplates the coexistence of local and federal law,
we are bound by Skysign’s no preemption conclusion. Sky-
sign, 276 F.3d at 1118 (“[W]e conclude that the application
of Honolulu’s ordinances does not impede the federal policy
or purpose in issuing [the] Certificates of Waiver.”). We rec-
ognize though, as we did in Skysign, that Congress itself, or
through the FAA, may have the authority to completely
occupy the field of banner towing or regulate it in such a way
that could preempt the Ordinance. See id. at 1116. We need
not decide that issue here, however, because in the present
appeal, no such affirmative regulations justify federal preemp-
tion.3 We now turn to the Center’s claim that the Ordinance
violates the First Amendment.

II.    THE ORDINANCE DOES NOT VIOLATE THE FIRST AMEND-
       MENT


   It is uncontested that the banner towing at issue is a form
of speech protected under the First Amendment. The Center
has a targeted message that it wishes to communicate. “But it
is also well settled that the government need not permit all
forms of speech on property that it owns and controls.” Int’l
Soc’y for Krishna Consciousness, Inc. v. Lee, 505 U.S. 672,
678 (1992). To assess a First Amendment free speech claim,
  3
    The Center requests that we take judicial notice of changes made to the
FAA Handbook on December 17, 2004, and a revised Certificate issued
to the Center on February 22, 2005, both of which went into effect after
the district court’s decision in November 2004. We deny the Center’s
request for judicial notice pursuant Federal Rule of Evidence 201 because
these documents were not before the district court and their significance,
if any, is not factored into the record on appeal. Consideration of these
documents and after-enacted changes is best left to the district court, not
to the court of appeals for initial analysis. There is good reason why we
generally do not consider issues for the first time on appeal—the record
has not been developed, the district court has not had an opportunity to
consider the issue, and the parties’ arguments are not developed against
the district court decision.
         CENTER FOR BIO-ETHICAL REFORM v. HONOLULU         7437
“we first must ‘identify the nature of the forum, because the
extent to which the Government may limit access depends on
whether the forum is public or nonpublic.’ ” Preminger v.
Principi, 422 F.3d 815, 823 (9th Cir. 2005) (quoting Corne-
lius v. NAACP Legal Def. & Educ. Fund, Inc., 473 U.S. 788,
797 (1985)).

  A.   THE AIRSPACE IS A NONPUBLIC FORUM

   [5] For purposes of First Amendment analysis, public prop-
erty fits into one of three main categories: (1) a public forum,
(2) a designated public forum, or (3) a nonpublic forum. Pre-
minger, 422 F.3d at 823. Any public property that is neither
a public nor a designated public forum is considered a non-
public forum. DiLoreto v. Downey Unified Sch. Dist. Bd. of
Educ., 196 F.3d 958, 965 (9th Cir. 1999).

   [6] Public fora are places “that have traditionally been
devoted to expressive activity,” such as public parks and side-
walks. Preminger, 422 F.3d at 823. “Content-based restric-
tions in public fora are justified only if they serve a
compelling state interest that is narrowly tailored to the
desired end.” Id. This level of review is known as strict scru-
tiny. Designated public fora are nonpublic fora that the gov-
ernment affirmatively opens to expressive activity. Id. As
with public fora, content-based restrictions on designated pub-
lic fora must pass strict scrutiny. Id.

   [7] Areas not traditionally or explicitly opened to expres-
sive activity are deemed nonpublic fora, which are subject to
a more lenient standard of scrutiny—restrictions on nonpublic
fora need only be reasonable and viewpoint neutral. Id. Exam-
ples of nonpublic fora include airport terminals, Lee, 505 U.S.
at 679, highway overpass fences, Brown v. Cal. Dep. of
Transp., 321 F.3d 1217, 1222 (9th Cir. 2003), and interstate
rest stop areas (including perimeter walkways), see Jacobsen
v. Bonine, 123 F.3d 1272, 1273-74 (9th Cir. 1997).
7438      CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
   [8] A review of the history, purpose, and physical charac-
teristics of the airspace at issue leads us to conclude that it is
a nonpublic forum. As to its history and purpose, the airspace
does not fit the public forum category because it is not among
those places that “have immemorially been held in trust for
the use of the public and, time out of mind, have been used
for purposes of assembly, communicating thoughts between
citizens, and discussing public questions.” Lee, 505 U.S. at
679. “[A] traditional public forum is property that has as ‘a
principal purpose . . . the free exchange of ideas.’ ” Id. (alter-
ation in original) (quoting Cornelius, 473 U.S. at 800).

   Like the airport terminal in Lee, the highway overpass
fences in Brown, and the interstate rest stops in Jacobsen, the
use of the airspace for banner towing is a relatively modern
creation that “hardly qualifies for the description of having
‘immemorially . . . time out of mind’ been held in the public
trust and used for purposes of expressive activity.” Lee, 505
U.S. at 680. In fact, one would be hard pressed to find another
forum that has had its access as historically restricted as U.S.
airspace. The FAA has strict regulations governing the air-
space and for more than twenty-five years Honolulu has regu-
lated aerial advertising. In light of the numerous restrictions
placed on the use of the airspace in and around Honolulu, its
principal purpose can hardly be characterized as “promoting
‘the free exchange of ideas.’ ” Id. at 682; see United States v.
Kokinda, 497 U.S. 720, 727 (1990) (contrasting a public
street, which is “a necessary conduit in the daily affairs of a
locality’s citizens” with a “postal sidewalk . . . constructed
solely to provide for the passage of individuals engaged in
postal business”).

   The physical characteristics of the airspace also underscore
that it is not a public forum. The airspace is not, as the Center
argues, an extension of the fora below, namely the beaches.
We do not express any opinion as to whether the beaches are
public fora because the record is not developed on this point
and this categorization is not necessary to our analysis. But
         CENTER FOR BIO-ETHICAL REFORM v. HONOLULU         7439
even assuming that the beaches are public fora, the airspace
above is not a public forum by extension.

   Spatial proximity to a public forum is determinative only if
the two areas are physically “indistinguishable.” See, e.g.,
United States v. Grace, 461 U.S. 171, 179 (1983) (sidewalks
leading to the United States Supreme Court building indistin-
guishable in both location and purpose from other public side-
walks and thus public fora). In Kokinda, the Supreme Court
explained Grace as requiring the location and purpose of the
property to be examined before it is deemed a public forum
by proximity or extension. 497 U.S. at 728-29. Examining the
location and purpose of the airspace surrounding the beaches
of Honolulu, the airspace is easily distinguishable from the
fora below. The airspace is physically separate from the
ground or beaches, requires special equipment and authoriza-
tion for access, and has never typically been a locus of expres-
sive activity.

   [9] Nor can the airspace be classified as a designated public
forum, which is created only when the government has “ex-
pressly dedicated the property for expressive conduct.” Prem-
inger, 422 F.3d at 824 (citing Widmar v. Vincent, 454 U.S.
263, 267 (1981)). The regulated airspace is the antithesis of
an “intentional[ ] opening [of] a nontraditional forum for pub-
lic discourse.” Cornelius, 473 U.S. at 802. The Ordinance
explicitly prohibits using Honolulu’s airspace as a forum for
expressive conduct and neither party cites a single example
where expressive activity was sanctioned to occur in Honolu-
lu’s airspace. Further, Honolulu’s airspace is not naturally
compatible with expressive activity.

   [10] We are thus left to examine the airspace as a nonpublic
forum, in which the Ordinance does not violate the First
Amendment as long as it is “(1) reasonable in light of the pur-
pose served by the forum and (2) viewpoint neutral.” Brown,
321 F.3d at 1222 (quotation marks omitted).
7440      CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
  B.   THE ORDINANCE IS VIEWPOINT NEUTRAL

   [11] The Ordinance’s prohibition against airborne signs or
advertising devices is viewpoint free. “Viewpoint discrimina-
tion is a form of content discrimination in which ‘the govern-
ment targets not subject matter, but particular views taken by
speakers on a subject.’ ” Id. at 1223 (citing Children of the
Rosary v. City of Phoenix, 154 F.3d 972, 980 (9th Cir. 1998)).
The Ordinance prohibits the “display in any manner or for any
purpose whatsoever any sign or advertising device” by an
“aircraft or other self-propelled or buoyant airborne object.”
The Ordinance says nothing about the content of the signs or
the views expressed. In contrast to the laws at issue in other
sign cases, the Ordinance makes no distinction between com-
mercial signs and other displays. See, e.g., Metromedia, Inc.
v. City of San Diego, 453 U.S. 490, 494-96 (1981). Nor does
it distinguish between commercial speech or political speech.
And, finally, the Ordinance draws no lines by subject matter
(such as countenancing speech on behalf of candidates and
yet restricting it on behalf of issue advocacy groups) or by
viewpoint (such as distinguishing among views on abortion).
In short, the prohibition is entirely neutral.

   The only relevant exception to the absolute bar on advertis-
ing is that the Ordinance permits “an identifying mark, trade
name, trade insignia, or trademark on the exterior of an air-
craft. . . . if the displayed item is under the ownership or regis-
tration of the aircraft’s or the airborne object’s owner.” § 40-
6.1(b)(1). This exception, which pertains to the external mark-
ing of an aircraft, is a common sense one. Honolulu would be
hard pressed to say that aircraft flying over the beach are pro-
hibited from displaying their name and logo, such as Hawai-
ian Airlines, Aloha Airlines, Quantas Airlines, or United
Airlines, when the FAA is charged with prescribing regula-
tions for identification of aircraft. 49 U.S.C. § 40103(b)(2).

  Despite the facial neutrality of the Ordinance, the Center
argues that the Ordinance is not viewpoint neutral because it
         CENTER FOR BIO-ETHICAL REFORM v. HONOLULU           7441
discriminates between commercial advertising and political
speech. Under the Ordinance, the Center argues, one could fly
the Goodyear Blimp carrying a commercial message, yet
would be prohibited from towing banners carrying the Cen-
ter’s political message. This argument mischaracterizes the
Ordinance.

   [12] It is true that once the government opens up a forum,
it may not discriminate on the basis of viewpoint. Police
Dep’t of Chicago v. Mosley, 408 U.S. 92, 96 (1972). But, the
Ordinance does not do so. The identifying mark exception dif-
ferentiates only as to the medium used for the expression—
i.e., identifying marks on aircraft versus towed banners—and
not on the basis of any particular viewpoint. For example, the
district court posited that the Center could fly a blimp having
its own identifying marks, even if its marks contained a politi-
cal message:

    Plaintiffs complain that, under the wording of the
    statute, the Goodyear Blimp would be allowed to
    cruise the skies above Waikiki beach, while their
    tow-banners would not. This is not discrimination. If
    Plaintiffs so choose, they too would be permitted to
    purchase a dirigible or other aircraft, emblazon their
    own identifying mark on it, and fly above the beach.

Center for Bio-Ethical Reform, 345 F. Supp. 2d at 1137.

   [13] Although the Center’s hypothetical blimp would be
limited to displaying an “identifying mark, trade name, trade
insignia, or trademark” that is valid or permissible under the
applicable FAA and trademark laws, the Center would none-
theless be as free as Goodyear to fly its own craft with identi-
fying markings. Thus, to the extent permitted by federal law,
and having nothing to do with the Ordinance, the Center
could employ an “identifying mark” if it were “under the
ownership or registration of the aircraft’s or the airborne
object’s owner.” § 40-6.1(b)(1). The result is that if the Center
7442     CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
has an aircraft or airline and an identifying mark, such as “Pro
Life for America” or “Abortion Kills,” it too could fly the air-
craft over Honolulu’s beaches without running afoul of the
Ordinance. Of course such a scheme may be subject to federal
restrictions that are not before us in this appeal. The Ordi-
nance easily passes the hurdle of viewpoint neutrality.

  C.   THE ORDINANCE IS REASONABLE

   [14] “The reasonableness analysis focuses on whether the
limitation is consistent with preserving the property for the
purpose to which it is dedicated.” Brown, 321 F.3d at 1222
(quotation marks omitted). Any limitation must “fulfill a
legitimate need[,] [y]et, in a nonpublic forum, the restriction
need not constitute the least restrictive alternative available.”
Preminger, 422 F.3d at 824.

   [15] It is well established that regulation for purposes of
preserving aesthetics and promoting safety falls within the
legitimate and substantial interests of local governments. See
e.g., Metromedia, 453 U.S. at 507-08 (“Nor can there be sub-
stantial doubt that the twin goals that the ordinance seeks to
further—traffic safety and the appearance of the city—are
substantial governmental goals.”); see also Members of City
Council of Los Angeles v. Taxpayers for Vincent, 466 U.S.
789, 805 (1984) (“It is well settled that the state may legiti-
mately exercise its police powers to advance esthetic val-
ues.”); Ackerley Commc’ns of the N.W., Inc. v. Krochalis, 108
F.3d 1095, 1099 (9th Cir. 1997) (“[T]he Court has continued
to rely on its conclusion in Metromedia that a city’s interest
in avoiding visual clutter suffices to justify a prohibition of
billboards . . . .”). The government need not provide detailed
proof that the regulation advances its purported interests of
safety and aesthetics. Krochalis, 108 F.3d at 1099-1100 (“As
a matter of law Seattle’s ordinance, enacted to further the
city’s interest in esthetics and safety, is a constitutional
restriction on commercial speech without detailed proof that
           CENTER FOR BIO-ETHICAL REFORM v. HONOLULU                 7443
the billboard regulation will in fact advance the city’s inter-
ests.”).

   [16] The Ordinance fulfills several legitimate needs, includ-
ing preserving the economically vital scenic beauty of Hono-
lulu and minimizing traffic safety hazards for motorists and
pedestrians. Although both of these goals are surely legiti-
mate, preservation of the visual beauty of Honolulu’s coastal
and scenic areas is of paramount importance. The district
court succinctly emphasized this point:

      To say that the ordinance is designed to mitigate
      “aesthetic harm” is misleading in Hawaii. In actual-
      ity, the ordinance is designed to protect what is per-
      haps the state’s most valuable and fragile economic
      asset—the natural beauty upon which Hawaii’s tour-
      ism economy relies. Revenue generated by tourism
      accounts for almost one quarter of Hawaii’s gross
      domestic product, and almost one third of the state’s
      employment. Studies, and common sense, indicate
      that the scenic beauty of Hawaii is one of the pri-
      mary factors weighed by potential visitors when
      determining whether to spend their vacation dollars
      in Hawaii or another locale. More than half a billion
      dollars have been spent in the past five years on
      improvements to public areas in Waikiki, and a large
      proportion of these expenditures were for primarily
      aesthetic enhancements.

Center for Bio-Ethical Reform, 345 F. Supp. 2d at 1134.

   These legitimate needs are also consistent with the pur-
poses to which Honolulu has dedicated the airspace—
aesthetic enhancement of the community and reduction of
visual distractions for travelers on the ground.4 Although the
  4
    The airspace also has the obvious purpose of air travel, but this is an
area which the FAA has plenary power to regulate. We therefore look only
to the scope of purposes for which Honolulu has the ability to regulate.
7444     CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
legitimate needs and the purposes are congruent, it does not
mean this inquiry is circular. Rather, it shows that, under the
Ordinance, Honolulu has regulated the airspace to accomplish
its legitimate purposes.

   [17] The Center’s suggestion that the Ordinance’s identify-
ing mark exception belies these purposes because aircraft
painted with trademarks would certainly upset the aesthetics
and produce visual distractions is both speculative and a
non sequitur. Does the Center suggest that only an ordinance
prohibiting all aircraft or all aircraft markings would be per-
missible? Honolulu’s regulatory authority does not require it
to exercise that power in a pristine, perfect sense, only in a
reasonable manner. In other words, nothing requires Honolulu
to turn the airspace into an air wilderness zone. Nor could it
do so, given the FAA’s plenary power over the airspace. Sig-
nificantly, nothing in this record supports any claim that the
Ordinance was aimed at the Center or its message. See Tax-
payers for Vincent, 466 U.S. at 804 (prohibition of sign on
public property upheld in part because “there is not even a
hint of bias or censorship in the City’s enactment or enforce-
ment of this ordinance” and “[t]here is no claim that the ordi-
nance was designed to suppress certain ideas that the City
finds distasteful or that it has been applied to appellees
because of the views that they express.”). We conclude that
the Ordinance is reasonable.

  D.   THE ORDINANCE DOES NOT FORECLOSE A
       TRADITIONALLY     IMPORTANT   MEDIUM     OF
       COMMUNICATION OR LEAVE THE CENTER WITHOUT A
       PRACTICAL SUBSTITUTE

   We consider one final point in our First Amendment analy-
sis. Citing City of Ladue v. Gilleo, 512 U.S. 43 (1994), the
Center argues that the Ordinance violates the First Amend-
ment because it forecloses an entire medium of communica-
tion, namely banner towing. We disagree.
          CENTER FOR BIO-ETHICAL REFORM v. HONOLULU          7445
  In One World One Family Now v. City and County of
Honolulu, 76 F.3d 1009 (9th Cir. 1996), we examined Ladue,
and underscored several key aspects of the opinion that are of
particular import to the present appeal. As we explained in
One World:

    In Ladue, the Court struck down a broad ban on the
    display of signs on private residential property. The
    opinion rested heavily on the view that the city’s
    ordinance closed off a “unique and important” mode
    of expression for which there is “no practical substi-
    tute.” The Court explained that “[d]isplaying a sign
    from one’s own residence often carries a message
    quite distinct from placing the same sign someplace
    else, or conveying the same text or picture by other
    means.”

    ...

    A message on one’s person or home has a unique
    effect because it “provide[s] information about the
    identity of the ‘speaker’ [which is] an important
    component of many attempts to persuade.”

76 F.3d at 1015 (citations omitted).

   Ladue was concerned with the elimination of “a common
means of speaking,” 512 U.S. at 55, that was “a distinct and
traditionally important medium of expression,” id. at 57 n.16,
that had a unique ability to “provide information about the
identity of the ‘speaker,’ ” id. at 56, and that in light of these
special attributes had “no practical substitute,” id. at 57. Ban-
ner towing possesses none of these attributes.

   [18] Banner towing is neither a common means of speaking
nor a distinct and traditionally important form of expression.
Compare id. at 55 (striking down ban on traditionally impor-
tant residential signs and reciting cases protecting other tradi-
7446     CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
tionally important mediums such as distribution of pamphlets
and handbills and door to door dissemination of literature)
with Lee, 505 U.S. at 680 (holding that an airport is not a pub-
lic forum in part because of “the lateness with which the mod-
ern air terminal has made its appearance” and the refusal of
airport operators to intentionally open them to speech activ-
ity).

   The Center does not argue, nor could it, that banner towing
provides a unique ability to convey information about the
speaker’s identity. As observed by the district court, banner
towing achieves the opposite result: “[Ladue] dealt with com-
munication by an individual through means that tied the mes-
sage to the speaker’s identity. This [scenario] is precisely the
opposite of what [the Center] seeks: a means by which to
insulate itself from its unwilling audience.” Center for Bio-
Ethical Reform, 345 F. Supp. 2d at 1135.

   Faced with these difficulties, the Center bases its argument
almost entirely on the “no practical substitute” prong, arguing
that the remaining modes of communication are inadequate
because banner towing is uniquely efficient in expressing the
Center’s message to the large crowds gathered on the beaches
of Honolulu. The Center misreads what is meant by “no prac-
tical substitute.” Ladue teaches that in evaluating the ade-
quacy of substitutes, the court must look to the unique
communicative importance of the foreclosed medium in rela-
tion to the individual speaker. 512 U.S. at 56. For example,
in Ladue the unique source identifying ability of a sign in
front of an individual’s home coupled with the fact that such
signs are “unusually cheap and convenient” made other chan-
nels of communication unacceptable. Id. at 56-57. The Court
distinguished how this analysis would differ if the speaker
were a business or political organization:

    The precise location of many other kinds of signs
    (aside from “on-site” signs) is of lesser communica-
    tive importance. For example, assuming the audience
         CENTER FOR BIO-ETHICAL REFORM v. HONOLULU          7447
    is similar, a commercial advertiser or campaign pub-
    licist is likely to be relatively indifferent between
    one sign site and another. The elimination of a cheap
    and handy medium of expression is especially apt to
    deter individuals from communicating their views to
    the public, for unlike businesses (and even political
    organizations)[,] individuals generally realize few
    tangible benefits from such communication.

Id. at 57 n.15. Unlike the yard signs in Ladue, banner towing
does not have a unique source-identifying ability. Absent
some unique source-identifying ability, the fact that banner
towing is inexpensive and efficient, standing alone, does not
mean the Ordinance is unconstitutional.

   [19] The Supreme Court has already determined that there
is no constitutional right to engage in the cheapest, easiest, or
most far-reaching form of communication:

    That more people may be more easily and cheaply
    reached by [a particular means of communication],
    perhaps borrowed without cost from some zealous
    supporter, is not enough to call forth constitutional
    protection for what those charged with public wel-
    fare reasonably think is a nuisance when easy means
    of publicity are open.

Kovacs v. Cooper, 336 U.S. 77, 88-89 (1949). Even though
the banner may be preferable in its communicative efficiency,
there is little likelihood that the Center will be chilled in its
efforts to spread its message to its intended audience through
ample and adequate alternative channels. See Ladue, 512 U.S.
at 56-57 & n.15. The Center has at its disposal a wide range
of practical and effective means of communicating its
message—from television to direct mail, email, leaflets, hand-
held signs and old-fashion stumping, Hyde Park style.

   [20] We therefore hold that the Ordinance does not violate
the First Amendment because it is a reasonable and
7448        CENTER FOR BIO-ETHICAL REFORM v. HONOLULU
viewpoint-neutral restriction on speech in a nonpublic forum;
as expressed in Ladue, the Ordinance does not foreclose a
unique and traditionally important mode of expression for
which there is no practical substitute.

III.    THE ORDINANCE DOES NOT VIOLATE THE EQUAL
        PROTECTION CLAUSE

   [21] “[T]he viability of equal protection claims relating to
expressive conduct is contingent upon the existence of a pub-
lic forum. Only when rights of access associated with a public
forum are improperly limited may we conclude that a funda-
mental right is impinged.” Monterey County Democratic
Cent. Comm. v. U.S. Postal Serv., 812 F.2d 1194, 1200 (9th
Cir. 1987) (citing Perry Educ. Ass’n v. Perry Local Educa-
tors’ Ass’n, 460 U.S. 37, 54-55 (1983)). Because the airspace
is a nonpublic forum, the Center has no claim to a fundamen-
tal right of access, and the Ordinance need only “rationally
further a legitimate state purpose.” Id. The Ordinance meets
this minimal scrutiny, as we have already noted. We also
emphasize that, consistent with the Equal Protection Clause,
the Ordinance is viewpoint neutral and a reasonable restric-
tion:

       [U]nder the Equal Protection Clause, not to mention
       the First Amendment itself, government may not
       grant the use of a forum to people whose views it
       finds acceptable, but deny use to those wishing to
       express less favored or more controversial views. . . .
       This is not to say that all [expressive conduct] must
       always be allowed. We have continually recognized
       that reasonable . . . regulations . . . may be necessary
       to further significant governmental interests. . . .
       [U]nder an equal protection analysis, there may be
       sufficient regulatory interests justifying selective
       exclusions or distinctions. . . .

Mosley, 408 U.S. at 96-98 (citations omitted). For these rea-
sons, the Ordinance passes constitutional scrutiny.
         CENTER FOR BIO-ETHICAL REFORM v. HONOLULU     7449
                       CONCLUSION

   The district court properly granted Honolulu’s motion for
summary judgment. Federal law does not preempt the Ordi-
nance. Nor does the Ordinance violate the First Amendment
or the Equal Protection Clause of the Fourteenth Amendment.
Honolulu’s airspace is a nonpublic forum, and the Ordinance
is reasonable, viewpoint neutral, and rationally related to
legitimate governmental interests.

  AFFIRMED.
