Eleventh Circuit Vacates DOT Order Withdrawing Delta-Aeromexico Antitrust Immunity

The U.S. Court of Appeals for the Eleventh Circuit, on August 20, 2026, issued an opinion in Delta Air Lines, Inc. and Aerovias de Mexico, S.A. de C.V. v. U.S. Department of Transportation vacating a September 2025 order issued by the U.S. Department of Transportation¹ (DOT Order) that revoked the antitrust immunity (ATI) held by Delta Air Lines and Aeromexico.

In reaching its decision, the court reiterated that the standard of review of agency decisions of this type tends to be deferential, with courts reversing agency decisions only if they are "arbitrary and capricious" or otherwise unsupported by fact or law.² In striking down the DOT Order, the court determined that DOT's action was "arbitrary and capricious" in part because 1) DOT focused almost exclusively on competitive conditions for flights operating between the U.S. and Mexico City's Benito Juárez International Airport (MEX) and failed to analyze the broader impact of the Delta-Aeromexico joint venture on all U.S.-Mexico markets and 2) DOT had applied different standards of review to other joint arrangements that had been approved previously. As the court observed: "DOT did not reasonably explain why it conducted a far more limited market analysis in this case than it has always done in the past or why it imposed a requirement for approval of the joint venture that it did not require of similar joint ventures it approved in Japan."³

On the first point, the court reasoned: "The petitioners argue that DOT's final order was arbitrary and capricious because it relied on its concerns about competition at MEX, a single airport, in a manner that was inconsistent with DOT's precedent, which has historically involved a more complete market analysis. DOT argues that the final order can be squared with its precedent because it conducted a more complete evaluation of the relevant markets when it approved the joint venture in 2016 and this case, unlike the precedent the petitioners point to, is distinguishable because it involved revoking a joint venture's approval. We agree with the petitioners that DOT abruptly departed from its uniform precedent of conducting a comprehensive market analysis without reasonably explaining such a departure."⁴

On the issue of the disparate treatment of joint ventures operating in the U.S.-Japan market, the court observed: "DOT did not treat like cases alike because it held the petitioners to a higher standard for approval than the Japanese joint venture applicants when it made compliance with an open skies agreement at MEX necessary for approval in this case but approved two Japanese joint ventures despite the lack of an open skies agreement that included Haneda. And the final order does not adequately explain why the lack of open skies at MEX (an all-cargo ban and restrictive slot policies) mandated terminating approval of the joint venture when DOT has approved two joint ventures in Japan despite the lack of open skies at Haneda."⁵

Although the court's decision resolves the immediate issue of the continuation of the Delta-Aeromexico alliance,⁶ larger questions remain about the impact of this decision on future DOT alliance reviews, particularly in the face of continued constraints on access to slot-controlled airports served by other ATI-immunized joint ventures.

Footnotes

1 Joint Application of Delta Air Lines, Inc. Aerovias De Mexico, S.A. De C.V. Approval of and Antitrust Immunity for Alliance Agreements, Docket DOT OST 2015-0010, Final Order, DOT Order 2025-9-16, (issued Sept. 16, 2025).

2 See Opinion at 13.

3 Opinion at 3.

4 Opinion at 14.

5 Opinion at 20.

6 The DOT Order revoking ATI from the Delta-Aeromexico Joint Venture had been stayed pending the issuance of the court's opinion in this case. The case is subject to appeal by either party to the U.S. Supreme Court, which would determine whether or not to issue a Writ of Certiorari agreeing to review the case.

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