238 F.3d 1300 (11th Cir. 2001)
DELTA AIR LINES, INC., Plaintiff-Appellant,v.AIR LINE PILOTS ASSOCIATION, INTERNATIONAL, ET AL., Defendants-Appellees.
No. 00-16472D.C. Docket No. 00-03207-CV-WBH-1
UNITED STATES COURT OF APPEALS,ELEVENTH CIRCUIT.
January 18, 2001

Appeal from the United States District Court for the Northern District of Georgia
Before TJOFLAT, BARKETT and MAGILL*, Circuit Judges.
TJOFLAT, Circuit Judge:


1
This case is before the court on Delta Air Lines' appeal of the district court's  denial of a preliminary injunction against the Air Line Pilots Association.  Because we find concerted action on the part of the pilots and because the Air  Line Pilots Association has a duty under the Railway Labor Act, 45 U.S.C.  152  First, to prevent such action, we reverse and remand to the district court with  instructions to issue an appropriate injunction.

I.
A.

2
Delta Air Lines, Inc. ("Delta") and the Air Line Pilots Association,  International ("ALPA") are parties to a collective bargaining agreement ("CBA")  that governs the terms and conditions of employment for over 9,800 pilots  employed by Delta.1 Delta and ALPA commenced negotiations for a new CBA in  September 1999. These negotiations are ongoing.


3
In the midst of these ongoing negotiations, Delta pilots began to decline to fly  "overtime." Overtime is built into Delta's flight schedule, accounting for  approximately five to seven percent of scheduled flights, and derives from the  CBA.2 "Overtime" is in some ways a misnomer, for this is really unscheduled  "open time" on the flight schedule in which pilots may volunteer to fly  additional flights above their pre-arranged flight schedule. Although Delta  maintains a pool of reserve pilots to operate flights in the event a scheduled  pilot is unavailable, it relies upon pilots to "pick up" these overtime flights  in order for Delta to operate all of its scheduled flights.3 A pilot has the  right, under the CBA, to exercise his or her individual choice and decline to  pick up overtime flights. Additionally, a pilot can avoid being assigned to  operate overtime flights by exercising his or her CBA rights not to answer a  telephone call and not to return a telephone call to Delta; pilots may not be  assigned to overtime flying unless they have spoken with Crew Scheduling.


4
Although each individual pilot may make personal choices about how and whether  to work overtime, Delta relies upon many of the pilots choosing to work this  open time to fulfill its scheduled flights. If all of Delta's pilots were to  refuse to pick up additional flights and refuse to work overtime, Delta would  not be able to operate its full complement of flights. Although there are some  alternatives available to Delta under the CBA, including raising the "cap" on  pilot hours in a given month, staffing flights with reserves or management  pilots, and pre- canceling flights and rebooking passengers in advance, these  alternatives are limited and generally do not allow Delta to fly its full  complement of scheduled routes.


5
Beginning in November 2000, apparently just in time for holiday travel, Delta  pilots intensified their "no-overtime campaign."4 This action by the pilots,  viewed in the context of the holiday travel season and the ongoing labor  negotiations between ALPA and Delta, leads to the obvious inference that the  pilots are seeking to pressure Delta into making concessions in the negotiations  for a new CBA.


6
The effects of the pilots' no-overtime campaign are evident from Delta's flight  statistics. Historically, Delta cancels no more than one or two of 2,700 flights  daily due to lack of pilots. However, in November 1999, pilots averaged 2,053  daily requests for overtime; in November 2000 they averaged only 1,276 daily  requests. In the first three days of December 1999, pilots averaged 1,678 daily  requests; in those same days in December 2000 they averaged 503 requests. Delta  canceled a total of ten flights due to pilot shortages for the month of November  1999, while it canceled 375 flights in November 2000. In the first three days of  December 1999, Delta had no cancellations; in the first three days of December  2000 Delta canceled 386 flights.5 Clearly, the pilots' efforts to refuse  overtime is affecting both Delta's flight schedule and the traveling public.6


7
In the midst of the no-overtime campaign by the pilots, Delta tried to work with  ALPA by enlisting ALPA's assistance in ending the pilots' concerted no-overtime  campaign. During this time, ALPA issued a number of directives to the pilots  advising them of their rights under the CBA regarding overtime; ALPA recommended  flying overtime at premium rates - green slip flying. By November 2000, when  some pilots were advising (and sometimes threatening) other pilots not to seek  or fly overtime, the Delta Master Executive Council of ALPA ("MEC")7 advised  pilots several times, through several media, that pilots should respect the  choices of others regarding overtime and that whether to fly overtime was the  individual choice of each pilot. These steps by ALPA and the MEC had no  measurable effect on the pilots' no-overtime campaign. Delta was unable to  overcome the no-overtime campaign either through compensatory scheduling methods  or through ALPA's communications; therefore, Delta filed the present action.

B.

8
Delta filed a verified complaint on December 5, 2000 in the district court for  the Northern District of Georgia. The complaint alleged an unlawful job action  in violation of the Railway Labor Act ("RLA"), 45 U.S.C.  151-188.8 The  complaint named fifty-one defendants, including ALPA, the MEC and its officers,  and several individual pilots.9 Delta filed motions for a temporary restraining  order ("TRO") and a preliminary injunction on December 5. The district court  held a hearing on Delta's motions for a TRO and preliminary injunction on  December 6. The district court denied both motions on December 11. Delta filed  its Notice of Emergency Appeal the following day, December 12. Delta also moved  for an injunction pending appeal; we denied that motion on December 13. However,  in that same order, we granted Delta's motion for an expedited appeal. Moving on  the expedited basis, oral argument was heard on January 11, 2001.

II.
A.

9
The Railway Labor Act was passed in its initial form by Congress in 1926, with  the support of both the railroads and the unions. Although a number of  amendments have been introduced over the years, including extending the RLA to  the airline industry in 1936, the stated purposes have remained constant. The  first of the RLA's five listed purposes is "[t]o avoid any interruption to  commerce or to the operation of any carrier engaged therein." 45 U.S.C.   151a.10 To accomplish its purposes, especially this first purpose, the RLA  imposes a substantive duty upon "all carriers, their officers, agents and  employees to exert every reasonable effort to make and maintain agreements . . .  and to settle all disputes . . . in order to avoid any interruption to commerce  or to the operation of any carrier growing out of any dispute between the  carrier and the employees thereof." 45 U.S.C.  152 First. Because the statutory  structure reveals that this duty is at the "heart" of the RLA, see Bhd. of R.R.  Trainmen v. Jacksonville Terminal Co., 394 U.S. 369, 377- 78, 89 S. Ct. 1109,  1115, 22 L. Ed. 2d 344 (1969), and because of the legislative history of the  provision,11 the Supreme Court has clarified that section 152 First imposes a  legal duty enforceable by courts: "[W]e think it plain that [section 152 First]  was intended to be more than a mere statement of policy or exhortation to the  parties; rather, it was designed to be a legal obligation, enforceable by  whatever appropriate means might be developed on a case-by-case basis." Chicago  & N.W. Ry. Co. v. United Transp. Union, 402 U.S. 570, 577, 91 S. Ct. 1731, 1735,  29 L. Ed. 2d 187 (1971).


10
The RLA sets forth a detailed sequence of steps that carriers and their  employees (or their employees' representative) must undertake in negotiating  collective bargaining agreements. The RLA intentionally provides for slow  movements by all parties during this negotiation and bargaining process. As the  Supreme Court has recognized, the RLA "subjects all railway disputes to  virtually endless `negotiation, mediation, voluntary arbitration, and  conciliation.'" Burlington N. R.R. Co. v. Bhd. of Maintenance of Way Employees,  481 U.S. 429, 444, 107 S. Ct. 1841, 1850, 95 L. Ed. 2d 381 (1987) (quoting  Detroit & Toledo Shore Line R.R. Co. v. Transp. Union, 396 U.S. 142, 148-49, 90  S. Ct. 294, 298, 24 L. Ed. 2d 325 (1969)). The bargaining procedures of the RLA  are "purposely long and drawn out" in the hope that reason will, in time,  produce an agreement. Bhd. of Ry. and S.S. Clerks v. Fla. E. Coast Ry. Co., 384  U.S. 238, 246, 86 S. Ct. 1420, 1424, 16 L. Ed. 2d 501 (1966).


11
During the long negotiating process, the RLA seeks to protect the public,  carriers, and unions alike by imposing a legal duty upon carriers and unions to  maintain the status quo with respect to "rates of pay, rules, [and] working  conditions," even when there is a disagreement about the CBA. 45 U.S.C.   155-56; Consol. Rail Corp. ("Conrail") v. Ry. Labor Executives' Ass'n, 491 U.S.  299, 302-03, 109 S. Ct. 2477, 2480, 105 L. Ed. 2d 250 (1989).12 A failure by  either side to maintain the status quo during the bargaining and mediation  process may give rise to injunctive relief, even without the customary showing  of irreparable injury. Id.; see also Detroit & Toledo Shore Line R.R. Co., 396  U.S. 142, 90 S. Ct. 294 (upholding a status quo injunction).

B.

12
In cases where a carrier seeks injunctive relief against a union, a court must  look not only to the RLA, but also to the Norris-LaGuardia Act ("NLGA"), 29  U.S.C.  101-115, to determine whether the court has jurisdiction. As a general  rule, the NLGA prohibits courts from issuing injunctive relief in labor  disputes.13 29 U.S.C.  101, 104; Int'l Ass'n of Machinists v. Street, 367 U.S.  740, 772, 81 S. Ct. 1784, 1802, 6 L. Ed. 2d 1141 (1961) ("The [NLGA] expresses a  basic policy against the injunction of activities of labor unions."). The NLGA  also generally prohibits a court from holding a union responsible for illegal  acts of the union members. 29 U.S.C.  107(a) ("[N]o injunction or temporary  restraining order shall be issued on account of any threat or unlawful act  excepting against the . . . organization making the threat or committing the  unlawful act or actually ratifying the same after actual knowledge thereof.");  29 U.S.C.  106 ("No . . . organization shall be held responsible or liable . .  . for the unlawful acts of individual officers, members, or agents, except upon  clear proof of actual participation in, or actual authorization of, such acts,  or of ratification of such acts after actual knowledge thereof."). The NLGA also  prescribes procedural rules for civil proceedings in which an employer seeks an  injunction or TRO against its employees. For an injunction, live testimony with  opportunity for cross-examination is normally required after proper notice; for  a TRO, though, sworn affidavits may suffice if the complainant would suffer  "substantial and irreparable injury" without the TRO. 29 U.S.C.  107.

C.

13
The Supreme Court has stated that although the prescriptions and proscriptions  of the NLGA are clear, the NLGA "cannot be read alone in matters dealing with  railway disputes." Bhd. of R.R. Trainmen v. Chicago River & Ind. R.R. Co., 353  U.S. 30, 40, 77 S. Ct. 635, 640, 1 L. Ed. 2d 622 (1957). Rather, "[t]here must  be an accommodation of [the NLGA] and the [RLA] so that the obvious purpose in  the enactment of each is preserved." Id.14 The way to accommodate these two  statutes, in most circumstances, is to determine if specific provisions of the  RLA are implicated. If so, "the specific provisions of the [RLA] take precedence  over the more general provisions of the [NLGA]." Id. at 42, 77 S. Ct. at 641;  accord Pittsburgh & Lake Erie R.R. Co. v. Ry. Labor Executives' Ass'n, 491 U.S.  490, 513, 109 S. Ct. 2584, 2598, 105 L. Ed. 2d 415 (1989).


14
When a specific provision of the RLA is implicated, "the District Court has  jurisdiction and power to issue necessary injunctive orders [to enforce  compliance with the requirements of the RLA] notwithstanding the provisions of  the [NLGA]." Bhd. of R.R. Trainmen v. Howard, 343 U.S. 768, 774, 72 S. Ct. 1022,  1025, 96 L. Ed. 1283 (1952); see also Chicago & N.W. Ry. Co. v. United Transp.  Union, 402 U.S. 570, 91 S. Ct. 1731, 29 L. Ed. 2d 187 (1971) (holding that 45  U.S.C.  152 First creates a legal obligation which a court may enforce through  injunction, notwithstanding section 4 of the NLGA (29 U.S.C.  104)); Chicago  River, 353 U.S. at 42, 77 S. Ct. at 641 (holding that injunctive relief is  appropriate under the RLA when a specific provision is implicated,  notwithstanding the general provisions of the NLGA); Virginia Ry. Co. v. Sys.  Fed'n No. 40, 300 U.S. 515, 549-52, 57 S. Ct. 592, 600-02, 81 L. Ed. 789 (1930)  (holding that injunctive relief is proper under the RLA).15 Although the NLGA  usually deprives federal courts of jurisdiction in general categories of labor  disputes,16 federal courts retain jurisdiction "to enjoin compliance with  various mandates of the [RLA]." Int'l Ass'n of Machinists v. Street, 367 U.S.  740, 772, 81 S. Ct. 1784, 1802, 6 L. Ed. 2d 1141 (1961). However, this exception  for the RLA is limited, and an injunction usually may lie only if, in addition  to violation of a specific principle of the RLA, an injunction is the sole  practical, effective means of enforcing the Act. See Burlington N. R.R. Co. v.  Bhd. of Maintenance of Way Employees, 481 U.S. 429, 446, 107 S. Ct. 1841, 1851,  95 L. Ed. 2d 381 (1987).


15
It is clear that the substantive legal duty of 45 U.S.C.  152 First, is a  "specific provision" of the RLA and, moreover, is central to the purpose and  functioning of the RLA. Therefore, the provision takes precedence over the more  general provisions of the NLGA. This is not to say that the procedural standards  of the NLGA do not apply, but only that the substance of the RLA is controlling.  We therefore hold that when this specific provision of the RLA is implicated and  there is no other effective way to enforce the RLA, the NLGA does not prohibit a  federal court from issuing an appropriate injunction.

III.
A.

16
Contrary to ALPA's assertion, we hold that the district court had jurisdiction  to hear the initial complaint: It did not arise from a "minor dispute," which  would have rendered it subject to mandatory and exclusive arbitration under the  RLA.17 We reject ALPA's contention that the CBA "arguably" allows all pilots to  refuse to work overtime, when it is clear industry practice to structure flight  schedules with "open time" built in. The only reasonable explanation for this  customary practice is an expectation that not all of the pilots will choose to  refrain from working overtime at the same time; this is implicit in the CBA.  Further, this dispute centers on 45 U.S.C.  152 First, which imposes a  statutory obligation "to exert every reasonable effort to make and maintain  agreements." This clear statutory provision is at the heart of the RLA and is  clearly within the province of the federal courts to enforce. When the public  interest, commerce, and a clear statutory provision are implicated, we will not  shy away from holding the parties to their duties under the RLA so as to avoid  "any interruption to commerce." 45 U.S.C.  152 First.

B.

17
This is an appeal from the denial of a preliminary injunction. We have  jurisdiction to hear this appeal pursuant to 28 U.S.C.  1292, which permits  appeals from interlocutory orders of district courts "granting, continuing,  modifying, refusing or dissolving injunctions." We generally review a denial of  preliminary injunctive relief on an abuse of discretion standard. Siegel v.  LePore, 234 F.3d 1163 (11th Cir. 2000).18 We note that in  RLA cases a carrier need not show irreparable injury, a usual prerequisite for  obtaining an injunction, to enjoin a violation of the status quo because of the  strong public interest in enforcing the RLA. See Conrail, 491 U.S. at 303, 109  S. Ct. at 2480. However, even if we were to look at the traditional factors for  a preliminary injunction, we would still review de novo the district court's  application of the law. Haitian Refugee Ctr. v. Baker, 949 F.2d 1109, 1110 (11th  Cir. 1991) (per curiam) ("[I]f the trial court misapplies the law we will review  and correct the error without deference to that court's determination."); see  also Cuban American Bar Ass'n v. Christopher, 43 F.3d 1412, 1423-24 (11th Cir.  1995) ("[T]he district court misapplied the law governing the issues presented  in this case. Thus, we accord no deference to the district court's  determinations in granting the preliminary injunctions in this case."). Because  we find that the district court misapplied the law in the instant case by  failing to recognize the extent of ALPA's duty under 45 U.S.C.  152 First, we  accord no deference to the district court's misapplication of the law.

C.

18
The district court erred in failing to appreciate the depth and seriousness of  the duty to "make and maintain agreements" in a way so as "to avoid any  interruption to commerce or to the operation of any carrier." 45 U.S.C.  152  First. In the instant case, our focus is on ALPA's duty to maintain agreements  to avoid interruption of commerce.19 As the Supreme Court has stated, this  language of the RLA creates a substantive legal duty "enforceable by whatever  appropriate means might be developed on a case-by-case basis." Chicago & N.W.  Ry. Co., 402 U.S. at 577, 91 S. Ct. at 1735. An injunction is an appropriate  remedy to compel the performance of this legal duty. See Nat'l Airlines, Inc. v.  Int'l Ass'n of Machinists & Aerospace Workers, 416 F.2d 998 (5th Cir. 1969)  (approving of an injunction against the union to issue directives to its members  to restore the status quo when union members were engaging in unlawful "wildcat"  strikes).20


19
The district court made explicit findings that there was an "ongoing concerted  effort on the part of some Delta pilots to refuse overtime work." In its  "Findings," the district court analyzed the number of canceled flights and  pilots' reduced requests for overtime and found that "the statistics differ so  substantially that the difference can only be explained by the efforts of an  undisclosed number of pilots to undermine contract negotiations, seeking  leverage for a salary increase." The court did not rest solely on statistical  evidence, though, but looked to other evidence, including e-mails, "many of  which rise to the level of intimidation and harassment." The court found that  the "traveling public" and Delta are both harmed by the pilots' concerted  activity:


20
This reduction in requests for overtime is causing harm to Delta and the  traveling public. Delta has lost millions of dollars in revenues, rerouting  expenses, extra operating costs, and overnight hotel and meal vouchers.  Additionally, Delta has suffered loss in the form of good will and traffic  that is immeasurable. The public has suffered loss in time and money from the  delays and cancellations which is also immeasurable.


21
In spite of these findings, the court refused to issue an injunction against  ALPA and/or MEC. It based this refusal on the fact that "[n]either the Union  leadership [of ALPA] nor the [MEC] supports this effort [by the pilots] and both  have, in fact, counseled against it." While it is true that ALPA and the MEC  "counseled against" the efforts of the pilots, it is equally clear that these  union communiques were not effective in suppressing the pilots no-overtime  campaign.


22
The district court's error came in its decision that it would "not hold that a  union has an affirmative duty to end or prevent the unilateral unlawful activity  of its members." The RLA imposes such a duty on the union in section 152 First,  and the district court should have enforced that duty. It is possible, of  course, that ALPA has in fact done all that it can do in directing the pilots to  cease their no-overtime campaign. We seriously doubt this is the case, however.  What seems to be true is that while ALPA has admonished its members at Delta's  request, it has not made "every reasonable effort" as required by statute. 45  U.S.C.  152 First. ALPA is statutorily bound to do everything possible to  "maintain" the CBA so that commerce is not in any way interrupted. We are not  satisfied that ALPA has fulfilled this duty.21 Therefore, the district court, on  remand, should enjoin ALPA to take specific steps aimed at stopping the pilots'  no-overtime campaign and resuming normal operations of Delta's operations,  including its overtime scheduling.22


23
It is possible, although unlikely, that ALPA has lost control of its members and  that the pilots are truly acting contrary to ALPA's wishes and directives. If  this proves to be the case (which would become evident if the district court's  injunction against ALPA is ineffective at stopping the no-overtime campaign),  then National Airlines, Inc. v. International Ass'n of Machinists & Aerospace  Workers, 416 F.2d 998 (5th Cir. 1969), would apply. In National Airlines, the  union had lost control of its members (and conceded as much to the court) and  the members were conducting "wildcat strikes"; the union was admittedly  powerless to prevent this. In this circumstance, the airline came to the court  seeking permission to terminate some of the employees if they failed to work  under the terms of their CBA. (The airline approached the court because the RLA  would not have permitted the airline's self-help without judicial intervention.)  In National Airlines, the former Fifth Circuit allowed the airline, faced with  employees who were violating the CBA and a union that had lost control of its  members, to take direct action against the employees.


24
If ALPA cannot control the pilots, some of whom are admittedly violating the CBA  by advocating concerted action, then Delta may return to the district court for  additional relief. The district court would, at that point, join all appropriate  parties as defendants (presumably sua sponte) and enjoin them from engaging in  continued activity in violation of the CBA, under penalty of court sanction or  other adverse employment action.

D.

25
Because the general procedural provisions of the NLGA still apply to this  action, even though the anti-injunction portion of the NLGA does not, we must  address the hearing before the district court. ALPA complains that Delta did not  put on live testimony, with opportunity for cross-examination, as required by  the NLGA, 29 U.S.C.  107. While it is clear that section 107 requires live  testimony in order to obtain a temporary or permanent injunction in a labor  dispute, section 107 also provides alternate hearing requirements for a  complainant to obtain a TRO. A TRO may be obtained to remedy "substantial and  irreparable injury" on the basis of testimony under oath sufficient to justify  the court's issuance of the TRO. 29 U.S.C.  107. Reading the TRO and injunction  provisions together, the purpose of section 107 is not so much about requiring  live testimony, then, as it is about ensuring the presence of reliable evidence  before a court may enjoin parties to a labor dispute.


26
In the instant case, although Delta did not put on live testimony, both sides  presented sworn affidavits and a host of other evidence and testimony.23 This  evidence was largely undisputed - particularly as it related to the fact that  the pilots were undertaking concerted action. ALPA's counsel conceded at the  hearing that injunctive relief would be proper if Delta's pilots were engaged in  concerted activity that violated the status quo; the district court did not  hesitate to make explicit its finding of such concerted activity by the pilots  in its dispositive order, and even in its closing comments at the hearing  itself. Delta's evidence consisted of (1) written documents reflecting the  pilots' overtime boycott (mainly in the form of captured e-mail communications);  (2) union pronouncements and directives, which were concededly authentic; (3)  statements of union members acknowledging the existence of the overtime boycott,  which were concededly genuine; and (4) statistical evidence of the impact of the  ban, which was not challenged by ALPA. ALPA presented its own documentary  evidence, as well as relying upon some of the evidence presented by Delta. The  only material issue at the hearing was whether ALPA actively sponsored or  ratified the pilots' no-overtime campaign.


27
Given that there was no dispute about the reliability of the evidence, at least  as to the concerted action by the pilots, we believe the district court was  entitled to rely upon such evidence to make its determinations.24 See Ry.  Express Agency, Inc. v. Bhd. of Ry., Airline & S.S. Clerks, Freight Handlers,  437 F.2d 388, 395 (5th Cir. 1971) (holding that section 107 was not violated  when the district court used only briefs and affidavits to decide whether to  issue an injunction; live testimony with cross-examination was not required). The purpose of section 107 is served if the evidence is inherently reliable and  there is no harm to the parties. An analogy to the hearsay rule demonstrates the  propriety of this holding. Hearsay statements are generally excludable because  they suffer from a lack of reliability; reliability is generally established  through live testimony and cross-examination. However, there are exceptions to  the hearsay rule that do not contravene the Confrontation Clause, even though  they permit the introduction of out-of-court statements, because the statements  are inherently reliable.

IV.

28
The district court properly determined that Delta's pilots were engaged in an  unlawful no-overtime campaign. However, the district court improperly  interpreted the gravity and depth of ALPA's duty under the RLA to prevent such  an unlawful job action. Because there has been no showing that ALPA lacks  control over the pilots, reason dictates that ALPA has not done enough to  fulfill its statutorily mandated duty to "maintain" the agreement and avoid an  "interruption to commerce." Upon remand, the district court shall issue  appropriate injunctive relief directing ALPA to take further steps to end the  pilots' no-overtime campaign. Further steps may include issuing directives as  drafted by the court and threatening (or imposing) union sanctions for  violations, as permitted by ALPA's constitution.25 If ALPA complies with the  court's orders and the no-overtime campaign continues, Delta may return to the  district court for injunctive relief against individual pilots, as discussed  supra Part III.C.


29
REVERSED and REMANDED, with instructions.



NOTES:


*
 Honorable Frank J. Magill, U.S. Circuit Judge for the Eighth Circuit, sitting    by designation.


1
 Delta is a common carrier by air engaged in the transportation of passengers and  freight in intrastate and interstate commerce throughout the United States. ALPA  is a labor organization that is the exclusive bargaining representative of  Delta's pilots.


2
 Under the current CBA, Delta schedules flights for public purchase, hires and  trains pilots to operate those flights, places the flights in monthly pilot  schedules that pilots bid to operate, maintains a number of "reserve pilots" to  operate flights in the event that scheduled pilots become unavailable, and  offers "open time" flights to pilots for flying as "overtime" above their  schedule.


3
 There are three kinds of "overtime" flights: White Slip, Green Slip, and Green  Slip with Conflict. White Slip flying, the most common kind of overtime (an  average of 6.77% of the total pilot credit hours per month from October 1, 1999  to September 30, 2000 were accounted for by white slip flying), is done at  regular contract rates. Green Slip and Green Slip with Conflict are flown at  premium rates, but do not reduce the availability of a particular pilot for  overtime in subsequent months. Pilots generally fly a monthly work schedule for which they have bid, according  to their training on particular equipment and seniority. A number of pilots,  usually between fifteen and twenty-five percent, are scheduled as reserves. Open  time may be assigned to reserves, if they are available. Generally, though, open  time flights are filled by pilots who voluntarily pick up open time; this  increases a pilot's flight hours and income. Pilots who desire premium pay may  choose to fly Green Slip rather than White Slip, which means that the pilot will  only be called upon after all pilots with White Slips and reserves for that day  have been used to fill vacancies. A pilot may also request to fly open time  hours on a flight which conflicts with the pilot's pre-assigned schedule; this  is Green Slip with Conflict. If this open time is awarded, then the pilot drops  his or her originally scheduled trip but receives payment for both the pre-  assigned trip and the trip actually flown.
Another method of flight staffing is "inverse assignment." Inverse assignment  involves Delta contacting available and qualified pilots, in inverse order of  seniority, to operate a flight. Inverse assignment duties pay premium (double)  rates, and inverse assignment occurs only after Delta has exhausted all pilots  volunteering for White Slips and Green Slips. Pilots often use answering  machines or fail to answer their telephones, which limits the value of inverse  assignment since a pilot may not be assigned unless he or she returns a call to  Crew Scheduling. Inverse assignment with conflict works in the same way as  regular inverse assignment, except that Delta calls upon pilots whose  pre-assigned schedule will conflict with the proposed inverse assignment.  Therefore, inverse assignment with conflict only occurs after Green Slips with  Conflict, as well as all other methods of filling pilot vacancies, are  exhausted.


4
 There is evidence in the record indicating that the pilots' actions had been  ongoing since late summer, but the no-overtime campaign increased in intensity  and resolve beginning in November.


5
 Delta has submitted additional information indicating that over 1,200 flights  were canceled between November 19, 2000 and December 10, 2000, and an additional  4,037 scheduled flights were canceled between December 11, 2000 and January 1,  2001 - all due to a lack of pilots.


6
 Delta's November 2000 cancellations affected 340,000 passengers who were booked  on the canceled flights. The cancellations during the first three days of  December 2000 affected an additional 30,000 passengers. Delta reports that an  additional 375,000 passengers were affected by the cancellation of 4,037  scheduled flights from December 11, 2000 to January 1, 2001.


7
 The MEC is the governing body for Delta's ALPA-represented pilots.


8
 Delta is a common carrier by air under the terms of the RLA, 45 U.S.C.  181.  ALPA is the legal representative for Delta's pilots under the terms of the RLA,  45 U.S.C.  152 Third.


9
 Delta also named one hundred "John Does" and one hundred "Jane Does" in its  complaint.


10
 Section 151a, in full, reads: The purposes of [the RLA] are: (1) To avoid any interruption to commerce or to  the operation of any carrier engaged therein; (2) to forbid any limitation upon  freedom of association among employees or any denial, as a condition of  employment or otherwise, of the right of employees to join a labor organization;  (3) to provide for the complete independence of carriers and of employees in the  matter of self-organization to carry out the purposes of [the RLA]; (4) to  provide for the prompt and orderly settlement of all disputes concerning rates  of pay, rules, or working conditions; (5) to provide for the prompt and orderly  settlement of all disputes growing out of grievances or out of the  interpretation or application of agreements covering rates of pay, rules, or  working conditions.


11
 In the House hearings on enacting this section of the RLA, Donald R. Richberg,  counsel for the organized railway employees supporting the bill, stated plainly  that section 152 First imposed a binding legal obligation on the parties. He  stated, "it is [the parties'] legal duty to exert every reasonable effort . . .  to settle all disputes, whether arising out of the abrogation of agreements or  otherwise, in order to avoid any interruption to commerce. In other words, the  legal obligation is imposed, and as I have previously stated, and I want to  emphasize it, I believe that the deliberate violation of that legal obligation  could be prevented by court compulsion." In further explaining why the provision  applied equally in general terms to both parties in RLA cases, he explained: We believe, and this law has been written upon the theory, that in the  development of the obligations in industrial relations and the law in regard  thereto, there is more danger in attempting to write specific provisions and  penalties into the law than there is in writing the general duties and  obligations into the law and letting the enforcement of those duties and  obligations develop through the courts in the way in which the common law has  developed in England and America. Hearings on Railroad Labor Disputes (H.R. 7180) before the House Committee on  Interstate and Foreign Commerce, 69th Cong., 1st Sess., 91 (1926) (quoted in  Chicago & N.W. Ry. Co. v. United Transp. Union, 402 U.S. 570, 577, 91 S. Ct.  1731, 1735, 29 L. Ed. 2d 187 (1971)).


12
 These status quo provisions of the RLA have been described by the Court as  "central to its design." Detroit & Toledo Shore Line R.R. Co. v. United Transp.  Union, 396 U.S. 142, 150, 90 S. Ct. 294, 299, 24 L. Ed. 2d 325 (1969).


13
 A "labor dispute" under the NLGA "includes any controversy concerning terms or  conditions of employment, or concerning the association or representation of  persons in negotiating, fixing, maintaining, changing, or seeking to arrange  terms or conditions of employment, regardless of whether or not the disputants  stand in the proximate relationship of employer and employee." 29 U.S.C.   113(c). The Supreme Court has explicitly held that the NLGA covers the  railroads, see Burlington N. R.R. Co. v. Bhd. of Maintenance of Way Employees,  481 U.S. 429, 440, 107 S. Ct. 1841, 1848, 95 L. Ed. 2d 381 (1987), and  therefore, by extension, the airlines.


14
 According to the Supreme Court, the two Acts have different purposes. On the one  hand, "[i]n adopting the Railway Labor Act, Congress endeavored to bring about  stable relationships between labor and management in this most important  national industry." Chicago River, 353 U.S. at 40, 77 S. Ct. at 640. It did this  because disputes between labor and management "had resulted in the aggregate  being serious enough to threaten disruption of transportation." Id. On the other  hand, "[t]he Norris-LaGuardia Act . . . was designed primarily to protect  working men in the exercise of organized, economic power, which is vital to  collective bargaining." Id.


15
 Appellee cites two circuit court cases purportedly on point regarding the  relationship or the RLA and the NLGA. See Fry v. Airline Pilots Ass'n, Int'l, 88  F.3d 831, 841-42 (10th Cir. 1996) (holding that the union could not be held  liable for damages in state tort law claim for the alleged harassment of pilots  who had worked through a strike without a showing of actual union authorization  or ratification); Airline Pilots Ass'n Int'l v. United Air Lines, 802 F. 2d 886,  905-06 (7th Cir. 1986) (stating in dicta that the airline's evidence of a  "sickout," using only statistical evidence and without identifying even one  pilot who had taken sick leave without actually being sick, was insufficient to  show a status quo violation at all, and therefore "would generally end the  discussion"). We find these cases to be inapposite.


16
 29 U.S.C.  104 provides: No court of the United States shall have jurisdiction to issue any restraining  order or temporary or permanent injunction in any case involving or growing out  of any labor dispute to prohibit any person or persons participating or  interested in such dispute (as these terms are herein defined) from doing,  whether singly or in concert, any of the following acts: (a) Ceasing or refusing to perform any work or to remain in any relation of  employment; (b) Becoming or remaining a member of any labor organization or of any employer  organization, regardless of any such undertaking or promise as is described in  section 103 of this title; (c) Paying or giving to, or withholding from, any person participating or  interested in such labor dispute, any strike or unemployment benefits or  insurance, or other moneys or things of value; (d) By all lawful means aiding any person participating or interested in any  labor dispute who is being proceeded against in, or is prosecuting, any action  or suit in any court of the United States or of any State; (e) Giving publicity to the existence of, or the facts involved in, any labor  dispute, whether by advertising, speaking, patrolling, or by any other method  not involving fraud or violence; (f) Assembling peaceably to act or to organize to act in promotion of their  interests in a labor dispute; (g) Advising or notifying any person of an intention to do any of the acts  heretofore specified; (h) Agreeing with other persons to do or not to do any of the acts heretofore  specified; and (i) Advising, urging, or otherwise causing or inducing without fraud or violence  the acts heretofore specified, regardless of any such undertaking or promise as  is described in section 103 of this title.


17
 "Minor disputes" are disputes over grievances or the interpretation or  application of agreements under the RLA. Consol. Rail Corp. ("Conrail") v. Ry.  Labor Executives' Ass'n, 491 U.S. 299, 302-07, 109 S. Ct. 2477, 2480-83, 105 L.  Ed. 2d 250 (1989). Exclusive jurisdiction over minor disputes rests with the  system adjustment board. See id. at 303-04 and 304 n.5, 109 S. Ct. at 2481 and  2481 n.5; Pyles v. United Air Lines, Inc., 79 F.3d 1046, 1049-50 (11th Cir.  1996). A decision of the appropriate system adjustment board with respect to an  issue of interpretation or application of a collective bargaining agreement is  final and binding on the parties in almost all circumstances. See Conrail, 491  U.S. at 303-04, 109 S. Ct at 2481. "Major disputes," by comparison, concern the formation or modification of  collective bargaining agreements. See Elgin, Joliet & E. Ry. v. Burley, 325 U.S.  711, 723-24, 65 S. Ct. 1282, 1289-90, 89 L. Ed. 1886 (1945). Conduct that  affects the status quo of a pre-existing agreement is a major dispute for  purposes of the RLA, and is properly brought before a federal court rather than  a system adjustment board. See Conrail, 491 U.S. at 302-03, 109 S. Ct. at 2480. If the conduct giving rise to an alleged status quo violation is arguably  permitted by the CBA, the resulting dispute is a minor dispute, because it  involves interpretation of the CBA. See id. at 307, 109 S. Ct. at 2483 ("Where  an employer asserts a contractual right to take the contested action, the  ensuing dispute is minor if the action is arguably justified by the terms of the  parties' [CBA]. Where, in contrast, the employer's claims are frivolous or  obviously insubstantial, the dispute is major.").


18
 A district court may grant preliminary injunctive relief only if the moving  party shows four things:  (1) it has a substantial likelihood of success on the merits; (2) irreparable  injury will be suffered unless the injunction issues; (3) the threatened injury  to the movant outweighs whatever damage the proposed injunction may cause the  opposing party; and (4) if issued, the injunction would not be adverse to the  public interest. Siegel v. Lepore, 234 F.3d 1163 (11th Cir. 2000). The  district court, had it properly applied the law, would have found that Delta met  all four of these factors. The substantial likelihood of success on the merits  is discussed infra Part III.C. Irreparable injury surely would be suffered by  Delta by canceling a number of flights, losing customer goodwill, and losing  revenues (although a showing of irreparable injury is not actually required  under Conrail, 491 U.S. at 303, 109 S. Ct. at 2480). There is no threatened  injury to the non-movant by the issuance of an injunction. Finally, the  injunction furthers the public interest by insuring the continued operation of  air travel on a major carrier.


19
 This section of the RLA imposes the same duty upon employees. 45 U.S.C.  152  First. The obvious implication from this is that Delta pilots may not  collectively disrupt Delta's flight operations, in contravention of the CBA, by  instituting a disruption in Delta's operations by way of a no-overtime campaign.  The district court found that such an unlawful no-overtime campaign was  occurring and properly applied this provision of the RLA against the pilots. The  district court did not enjoin individual pilots, though, and thereby did not  seek judicially to enforce this clear provision of the RLA.


20
 In Bonner v. City of Prichard, 661 F.2d 1206, 1209 (11th Cir. 1981) (en banc),  this court adopted as binding precedent all of the decisions of the former Fifth  Circuit handed down prior to the close of business on September 30, 1981.


21
 See Pan American World Airways, Inc. v. Indep. Union of Flight Attendants, 93  Lab. Cas.  13,307 (S.D.N.Y. 1981) (holding that an injunction should issue  against the union where the evidence showed that the union was encouraging "or  at least failing to discourage" a sickout in violation of the union's duty under  the RLA, 45 U.S.C.  152 First); Trans World Airlines, Inc. v. Int'l Ass'n of  Machinists and Aerospace Workers, 87 L.R.R.M. (BNA) 2556, 75 Lab. Cas.  10,312  (W.D. Mo. 1974) (holding that the union had failed to meet its duty under the  RLA, 45 U.S.C.  152 First, where the union did not authorize unlawful activity  by employees but did not take affirmative "reasonable" efforts to end such  activities by the union members).


22
 Because we agree with the district court that the individual pilots are making a  concerted, collective effort to reject overtime and institute an unlawful  disruption of Delta's operations, we need not rule on whether ALPA has ratified  the pilots' actions and is therefore directly responsible for the no-overtime  campaign. The duty of ALPA under the RLA is sufficiently high that even if it  has not sponsored or ratified the unlawful job action by the pilots, it has a  duty to end such unlawful action.


23
 Delta offered to put on its declarants as live witnesses, but the district court  decided to proceed without live testimony.


24
 We do not pass judgment at this time as to whether there was reliable and  undisputed evidence about ALPA's involvement in the no- overtime campaign. There  appears to be a genuine dispute over ALPA's involvement sufficient to  necessitate live testimony as contemplated by the NLGA, 29 U.S.C.  107.


25
 ALPA's constitution permits the union to discipline, fire, or expel any member  for a number of reasons, including "[a]cting in any manner to circumvent, defeat  or interfere with collective bargaining between the Association and an employer  or with existing collective bargaining agreements." ALPA Constitution and  Bylaws, Art. VIII, Sec. 1.A.



30
BARKETT, Circuit Judge, concurring specially, in which MAGILL, Circuit Judge,  joins:


31
I concur in the determination that under the law ALPA has an affirmative duty to  exert every reasonable effort to prevent or stop the unilateral unlawful  activity of its members and that it has not fulfilled that duty. Accordingly, I  agree that this case should be remanded for the entry of an appropriate  injunction requiring ALPA to take all reasonable steps to do so. However, any  discussion of possible actions based on the possibility that ALPA cannot control  its membership is premature.

