04:35 AM EDT, 07/22/2025 (MT Newswires) -- (Updates to add Aeromexico's comment in the last paragraph.)

Delta Air Lines ( DAL ) may lose a key part of its partnership with Aeromexico as the US government plans to take action against Mexico for breaching the 2015 US-Mexico Air Transport Agreement, the US Department of Transportation said Saturday.

The agency said it would propose revoking antitrust immunity for the Delta-Aeromexico joint venture, stopping the parties from coordinating on pricing, flight schedules, and revenue sharing.

Even if the immunity is removed, Delta would still be allowed to keep its investment in Aeromexico and maintain some aspects of the partnership, the department said.

The action is part of a broader response to Mexico's decision to cut flight slots and force cargo airlines to move out of Mexico City's main airport, citing congestion issues, the Department of Transportation said.

In an emailed statement to MT Newswires, Delta Airlines said that the termination of the partnership would "cause significant harm" to travelers between the two countries.

"We are reviewing the series of DOT orders regarding Mexico's adherence to the U.S.-Mexico Air Transport Agreement and look forward to working with the Trump Administration to resolve the issues raised in the orders," the airline said.

Aeromexico told MT Newswire it is reviewing the order and intends to submit a joint response with Delta in the coming days.