Federal Appeals Court Vacates DOT Order Against Delta and Aeromexico Antitrust Immunity

Delta Air Lines and Aeromexico have successfully challenged a Department of Transportation (DOT) order that aimed to revoke their antitrust immunity within their joint venture partnership. The 11th Circuit Court of Appeals vacated the DOT’s 2025 final order, deeming the agency’s rationale arbitrary and capricious. This ruling effectively restores the antitrust protections that allow the two airlines to coordinate schedules and operations on flights between the United States and Mexico.

The dispute traces back to a sharp change in the regulatory landscape during 2025 when the Trump administration revisited the 2016 approval of the joint venture’s antitrust immunity. The DOT’s reassessment followed a diplomatic conflict between the U.S. and Mexican governments concerning access to Mexico City’s Benito Juárez International Airport (MEX). The Mexican government had imposed slot controls at MEX amid capacity constraints and ongoing airport improvement projects, thereby limiting foreign airlines’ operations at this primary hub.

The DOT argued that restrictions at MEX disproportionately benefited Aeromexico, which holds the majority of the slots, giving it an anti-competitive advantage over U.S. carriers including Delta. This led the agency to conclude that the joint venture’s antitrust immunity should be terminated because the market conditions had fundamentally changed. However, the appeals court found that DOT’s market analysis was flawed because it assessed competition solely at MEX rather than considering the full bilateral market between the U.S. and Mexico.

Historically, the DOT’s evaluations of antitrust immunity in airline joint ventures involved analyzing the entire market across all relevant routes between two countries. The court ruled that the DOT diverged from this precedent without adequate justification in the 2025 order. The agency’s narrow focus on a single airport, rather than the entire transborder market, was deemed insufficient for revoking the immunity status.

The court also referenced past DOT approvals, including antitrust immunity for U.S.-Japan joint ventures that faced similar slot limitations at Tokyo’s Haneda Airport, to challenge the department’s argument that a complete Open Skies arrangement was a prerequisite. This precedent weakened the DOT’s position that Mexico’s slot restrictions undermined the joint venture’s legitimacy.

Despite vacating the DOT’s order, the ruling does not prevent the department from reopening the case. To successfully rescind the antitrust immunity, DOT would need to conduct a comprehensive market analysis compliant with regulatory standards and address the concerns identified by the appeals court. This process would require a carefully reasoned approach consistent with prior agency practice.

In response to the ruling, Delta stated that the joint cooperation agreement with Aeromexico has delivered increased travel options and connectivity for customers for nearly ten years while supporting jobs and economic growth in the United States. The airline expressed appreciation for the court’s review and emphasized its commitment to maintaining the benefits of the partnership.

The pathway ahead involves regulatory and legal complexities as the DOT must recalibrate its approach if it intends to challenge the joint venture’s immunity again. Meanwhile, the current status quo allows Delta and Aeromexico to continue operating their coordinated services under the protections of antitrust immunity, preserving their collaborative advantages in the critical U.S.-Mexico air travel market.