United Airlines (UA, Chicago O'Hare) is looking to take over two of the México City International slots which will become available in January 2020, when JetBlue Airways (B6, New York JFK) completely withdraws from the Mexican capital.

In order to receive antitrust immunity from the US Department of Transportation (DOT) for their transborder joint venture in 2017, Delta Air Lines (DL, Atlanta Hartsfield Jackson) and Aeroméxico (AM, México City International) were forced to divest 24 Mexico City slot pairs, with four slots granted to the low-cost carrier (LCC) jetBlue. However, less than three years later, all three of the US-based carriers awarded slots have exited the market - Alaska Airlines (AS, Seattle Tacoma International) in September 2018, Southwest Airlines (WN, Dallas Love Field) in March 2019, and jetBlue in January 2020.

Alaska had been allocated four Mexico City slot pairs, and used them to commence 2x daily services from Los Angeles International, and daily flights from San Francisco and San Diego International. Southwest was awarded four slot pairs, two to allow it to expand its existing Houston Hobby service to Mexico City, and one each for operations from Fort Lauderdale International and Los Angeles. The Texan LCC never launched the California route.

The DOT granted two Phase One slot pairs to jetBlue for a Fort Lauderdale service, two for the Orlando International route, and two Phase Two slots for a Los Angeles city pair, with the Californian city later changed to Boston and New York JFK routes.

In its application dated November 22, United says that it recognises that the DOT excluded it as an eligible carrier for the slots divested by Delta/Aeroméxico, but states that market "conditions have changed and the public interest requires a fresh look at, and reconsideration of, United’s eligibility for the divested slots." It continued: "rather than allow the slot pairs to go unused or be returned to Delta/Aeroméxico, the Department should award United the divested slot pair for its proposed service, which will enhance competition and provide significant consumer benefits."

If allocated, the Star Alliance carrier intends to use the slots to ramp-up its operations from San Francisco from 2x daily to a 3x daily service from the start of the Summer 2020 season. United currently uses its A319-100 fleet to operate the 1,685-nautical mile (3,027-kilometre) sector. The third daily rotation (flight UA1271), again using an A319, is planned to leave San Francisco at 1040L and arrive in Mexico City at 1715L the same day. Departure from the Mexican capital on flight UA1272 would be at 1810L and it would touch down in the US at 2105L.

The airline says that this proposed schedule will connect 67 US points and an additional 14 foreign points to Mexico City via San Francisco. The northbound flight from Mexico City will connect via San Francisco to 30 domestic and eight international points.

In addition to its San Francisco flights, United serves also Mexico City from Chicago O'Hare (11x weekly), Houston Intercontinental (39x weekly), New York Newark (20x weekly), and Washington Dulles (daily).