Appeals Court Vacates DOT Ruling, Keeping the Delta-Aeromexico Joint Venture Alive

Delta and Aeromexico have received a significant reprieve.

The 11th U.S. Circuit Court of Appeals has thrown out the Department of Transportation’s order that would have terminated the airlines’ joint venture, finding that the agency’s reasoning was “arbitrary and capricious.” The partnership remains intact, eliminating the disruption that had been hanging over U.S.-Mexico travel.

The Court Decision and How We Got Here

The dispute dates back to September 2025, when the DOT issued a final order revoking the antitrust immunity Delta and Aeromexico have had since 2016. That protection allowed the airlines to coordinate schedules, share revenue, and effectively operate as a single carrier on routes between the U.S. and Mexico.

Without it, their joint venture could no longer function the way it had for nearly a decade.

The DOT’s decision was driven largely by a broader dispute with the Mexican government. Mexico had reduced flight slots at Mexico City’s Benito Juárez International Airport (MEX) and moved cargo operations to Felipe Ángeles International Airport (NLU). The Trump administration argued that these measures violated the countries’ open skies agreement and gave Delta and Aeromexico an unfair advantage.

Delta and Aeromexico took the matter to court, and on August 20, 2026, the 11th Circuit ruled in their favor, vacating the DOT’s order for 2 key reasons.

For starters, the court found that the DOT had abandoned its previous approach without adequately explaining why. When the agency approved the joint venture in 2016, as well as when it evaluated comparable partnerships, it considered the entire U.S.-Mexico market, covering all 1,687 city-pair routes. In this case, however, the DOT focused primarily on conditions at MEX, an airport that handles only about 21% of U.S.-Mexico flights. According to the court, the agency failed to sufficiently justify that departure from its established methodology.

The court also found that Delta and Aeromexico had been subjected to a tougher standard than comparable joint ventures. It pointed to 2 American-Japanese partnerships that the DOT had approved despite similar restrictions at Tokyo’s Haneda Airport (HND). Haneda also limits U.S. carrier slots and prohibits all-cargo flights, yet the DOT did not take the same action against those partnerships.

The judges emphasized the court’s role in reviewing agency decisions, stating, “We are not a rubber stamp — courts retain a role, and an important one, in ensuring that agencies have engaged in reasoned decisionmaking.”

What This Means for Travelers

The biggest news for travelers is straightforward: The joint venture isn’t ending. Originally, the DOT had ruled that it had to cease as of January 1, 2026, though the airlines received a temporary stay — and continued operating as they always had — until an appeals court could rule on the case.

With this decision, Delta and Aeromexico can continue coordinating their schedules, sharing revenue, and operating the integrated network they’ve developed over the past decade.

That should be positive news for passengers traveling between the United States and Mexico. With the joint venture intact, the airlines can coordinate their networks instead of independently operating overlapping routes, which can help keep fares competitive. Their schedules can also remain synchronized, preserving convenient connections through major hub cities like Atlanta (ATL), Detroit (DTW), and Mexico City.

SkyTeam elite benefits would have remained available regardless, but maintaining the joint venture preserves the deeper level of cooperation between the airlines. That includes coordinated operations, shared lounge access, and the ability to more seamlessly earn and redeem miles across both carriers.

There is, however, an important qualification. The court did not rule that the DOT is permanently barred from ending the joint venture.

Instead, it determined that the agency failed to provide adequate justification for this particular order. The DOT could potentially try again if it addresses the court’s concerns, including conducting a broader market analysis and applying its standards consistently with comparable joint ventures.

The larger U.S.-Mexico dispute also remains unresolved. The MEX slot restrictions and relocation of cargo flights to NLU were at the heart of the DOT’s action, and neither issue has disappeared. If tensions between the governments continue to escalate, the DOT could revisit the joint venture with a revised case.

Final Thoughts

For the moment, Delta and Aeromexico’s nearly decade-old partnership is safe, and travelers for now will avoid the potential fare increases and schedule disruptions that could have followed its termination. That’s a clear positive for consumers in the short term.

But this probably isn’t the final chapter. The court didn’t rule that the joint venture itself was unquestionably in the public interest. Instead, it found that the DOT hadn’t properly supported its decision to end the arrangement. The agency now has an opportunity to go back to the drawing board.

If you have travel between the U.S. and Mexico planned for 2026, there’s no longer an immediate reason to worry about the joint venture disappearing. Still, the underlying dispute with Mexico is worth watching, because another DOT challenge remains possible.