Mexico City Airport to Restore Slots for US Carriers

Mexican authorities have told US airlines that they intend to return take-off and landing slots at Mexico City International Airport (MEX) that were withdrawn in 2022 and 2023. United Airlines disclosed the plan in a filing to the US Department of Transportation (DOT), saying Mexican officials informed IATA, American Airlines, Delta Air Lines and United on a call on 18 August 2025 that slots cut during the winter 2022/23 and summer 2023 seasons would be reinstated.

Key details were missing. The filing did not say how many slots would be returned or when, and neither the airport nor Mexico's Ministry of Infrastructure, Communications and Transportation (SICT) had confirmed the plan publicly at the time.

How the slot cuts happened

Mexico City International, also known as Benito Juárez International Airport or AICM, is Mexico's busiest airport and operates with two closely spaced runways that cannot be used independently. Under President Andrés Manuel López Obrador, the government decided to limit its capacity and push traffic towards the new Felipe Ángeles International Airport (AIFA), which opened in March 2022 about 45 km north of the city centre.

The reductions came in two steps:

• In 2022 the government brought in what it described as a temporary measure cutting the airport's hourly operations from 61 to 52.
• In 2023 Mexico's Federal Civil Aviation Agency (AFAC) confirmed a further cut from 52 to 43 operations an hour, effective 29 October 2023, citing terminal and airspace saturation studies.

Separately, a 2023 decree ordered all-cargo airlines to leave MEX, and US freighter operators were forced to move to AIFA. Cargo carriers argued that the move separated them from the bellyhold and logistics network that had grown up around the main airport. IATA opposed both measures and called them unilateral.

The US response

The DOT under Transportation Secretary Sean Duffy treated the slot withdrawals and cargo eviction as breaches of the 2015 US-Mexico Air Transport Agreement, which was designed to liberalise flying between the two countries. In an order issued on 19 July 2025, the DOT said Mexico had failed to comply with the agreement since 2022. It noted that the capacity cuts had been justified by construction intended to relieve congestion, which had not materialised three years later.

The department took two steps in July 2025:

• It proposed withdrawing approval and antitrust immunity for the joint venture between Delta Air Lines and Aeroméxico, which had allowed the two airlines to coordinate schedules, fares and capacity on US-Mexico routes since 2016.
• It required Mexican airlines to file their US schedules with the DOT and said it would scrutinise new services, signalling that Mexican carriers' growth in the US could be restricted.

Duffy said the measures were intended to protect US airlines and hold Mexico to the terms of the bilateral agreement. The signal from Mexico City on 18 August came weeks after these steps.

Why it matters

The US-Mexico market is one of the busiest international air markets in the world, and Mexico City is its most important point. Slot restrictions at MEX limited the ability of US carriers to add or retime flights at a time when Mexican carriers were growing their US networks. For passengers, constrained capacity at the capital's main airport contributes to higher fares and fewer convenient flight times.

For the Delta-Aeroméxico partnership, the dispute put a long-standing joint venture at risk because of a policy neither airline controlled. For cargo operators, the question was whether they would ever be allowed back into MEX.

What has happened since

• September 2025: The DOT issued a final order on 15 September 2025 ending antitrust immunity for the Delta-Aeroméxico joint venture from 1 January 2026.
• October 2025: On 28 October 2025 the DOT withdrew approval for 13 routes operated or planned by Aeroméxico, Volaris and Viva Aerobus, 11 of them from AIFA and two from MEX, and blocked further growth by Mexican carriers in the US.
• November 2025: On 12 November 2025 the US Court of Appeals for the Eleventh Circuit stayed the order to unwind the Delta-Aeroméxico joint venture while it heard the airlines' challenge.
• December 2025: Reports from Mexico said Mexican airlines had handed six slots at MEX to US carriers as part of the negotiations. Mexico also agreed to use slot management software and allow third-party oversight of slot compliance. Cargo operations were to remain at AIFA.
• May 2026: The two governments announced a preliminary agreement. Mexico committed to a technical capacity study at MEX benchmarked to international standards, a digital slot management system and fair slot access for US carriers. In return, the US agreed to recognise AIFA as part of the Mexico City airport system under the bilateral agreement and to allow the cancelled Mexican routes to reopen. A bilateral working group was set up to oversee the deal.
• August 2026: The Eleventh Circuit vacated the DOT order against the Delta-Aeroméxico joint venture, finding the department's reasoning arbitrary and capricious. The joint venture continues.