Delta, Aeromexico Antitrust Immunity Reinstated by Appeals Court

Court Vacates DOT Order

The 11th Circuit Court of Appeals has vacated a Department of Transportation (DOT) order concerning the joint venture between Delta Air Lines and Aeromexico. This ruling reinstates antitrust immunity for the two carriers. The court determined the DOT’s justification for revoking immunity was "arbitrary and capricious." This decision follows Delta’s lawsuit filed in October 2025.

Delta sought a review of the DOT’s final order, issued in September 2025. The appeals court emphasised its role in ensuring reasoned decision-making by government agencies. This outcome provides a temporary reprieve for the airlines’ close coordination on US-Mexico flights. The court delivered its judgment on Thursday, 20 August 2026.

Origins of the Dispute

The DOT initially approved antitrust immunity for Delta and Aeromexico in 2016. This agreement allowed the airlines to coordinate schedules across their US-Mexico flight network. However, a review of this immunity began in 2025 under the Trump administration. This review stemmed from a disagreement between the US and Mexican governments.

The dispute centred on access rights and slot allocations at Mexico City’s Benito Juárez International Airport (MEX). The US government accused Mexico of violating an ‘Open Skies’ agreement. It claimed Mexico limited slots at MEX and pressured US airlines to relocate to an alternative, less-utilised airfield.

Mexico stated slot controls at MEX were necessary due to capacity constraints and ongoing improvement works at the airport.

Narrow Market Analysis Rejected

The Department of Transportation believed Mexico’s slot restrictions unfairly benefited Aeromexico. Aeromexico holds the majority of slots at Benito Juárez Airport. The DOT concluded that Aeromexico’s, and by extension Delta’s, dominance at MEX was anti-competitive. The 11th Circuit Court, however, found the DOT’s market analysis too narrow.

Historically, the DOT reviewed the entire US-Mexico market for such agreements. For this specific order, the department focused solely on competition at MEX airport. The court ruled the DOT failed to explain this departure from its own precedent.

Furthermore, the court noted a previous US approval for Japanese joint ventures, despite similar carve-outs at Tokyo Haneda Airport, undermining the DOT’s argument for termination.

Future of the Partnership

Delta Air Lines responded to the judgment, highlighting the benefits of its joint cooperation agreement with Aeromexico. The airline stated the partnership has provided consumers with greater choice and connectivity for nearly a decade. It also supports US jobs and economic growth.

While the 11th Circuit Court vacated the 2025 order, this does not prevent the DOT from issuing a new termination order. However, any new order must address the specific issues raised by the court. The department would need to provide a more comprehensive market analysis or a clearer justification for any revised decision. This outcome means the Delta-Aeromexico partnership can continue its current operations for now.