US Transportation Officials Cite Anticompetitive Side Effects in US-Mexico City Markets

US lawmakers recently broke up a nine-year joint venture between Delta Air Lines and Aeromexico, claiming that it gave the carriers an unfair advantage in the US-Mexico City markets. While the government had floated the idea of a split since January 2024, the final order was not issued until September 15, 2025. The duo will now have a little over three months to part ways.

The partnership began in late 2016, when the carriers were granted antitrust immunity to coordinate schedules, pricing, and capacity on US–Mexico routes. Now, however, the DOT argues that the agreement has become anticompetitive, especially in the US–Mexico City market.

Delta and Aeromexico currently handle around 60 percent of flights between Mexico City International Airport and the United States, giving them clear dominance at a hub already criticized for favoritism in slot allocation and capacity. Officials claimed that the imbalance undermined the Open Skies agreement of 2015, which was designed to promote competition and expand market access.

The ruling is a major blow for the airlines, which have been near-seamless partners for the past nine years. Delta also holds a 20 percent equity stake in Aeromexico, though the DOT did not require it to sell.

“We are disappointed that the Department of Transportation has chosen to terminate its approval of the strategic and pro-competitive partnership between Delta and Aeromexico, a decision that will cause significant harm to US jobs, communities and consumers traveling between the US and Mexico,” read a statement from Delta. “We are reviewing the Department’s order and considering next steps.”

The split comes amid broader US–Mexico aviation tensions. The DOT has accused Mexico’s government of discriminatory airport slot policies and reducing permitted aircraft movements at Mexico City International, restricting access to US carriers. If this is a sign of more international scrutiny, however, other hubs like London Heathrow and Dublin could be the next to be called in.

FMI: www.delta.com