United Airlines (UA, Chicago O'Hare) has announced it will "temporarily" leave New York JFK with the onset of the Winter 2022/23 season as it has not been able to secure enough slots to make its presence cost effective.

"Given our current, too-small-to-be-competitive schedule out of JFK - coupled with the start of the Winter season where more airlines will operate their slots as they resume JFK flying - United has made the difficult decision to temporarily suspend service at JFK," the carrier said in a memo seen by Reuters.

The decision delivers on the carrier's recent warning that without a larger pool of permanent slots at the airport, it would have to abandon its short-lived attempt at returning to JFK. United argued that the current slot limits are outdated and do not consider the upgrades to the airport's infrastructure. The airline has been capped at 81 movements per hour since 2008.

The airline exited JFK in 2015 to focus on its base at New York Newark (while also retaining a presence at New York La Guardia). It returned to JFK in February 2021, using temporary slots made available during the COVID-19 pandemic. It currently operates just two routes out of JFK - to Los Angeles International and San Francisco, each 2x daily using B757-200 aircraft, according to the ch-aviation schedules module. This translates into a meagre 0.7% market share by scheduled weekly capacity.

United Airlines did not say whether it was planning to return to JFK in the long term.

Meanwhile, rival American Airlines (AA, Dallas/Fort Worth) admitted to losing valuable slots at JFK due to a miscalculation following its merger with US Airways (Phoenix Sky Harbor). Chief Commercial Officer Vasu Raja conceded during an ongoing antitrust trial about the airline's Northeast Alliance with JetBlue Airways (B6, New York JFK) that in 2019, the Federal Aviation Administration (FAA) stripped American Airlines of seven slots at the congested gateway as they were underutilised. Raja said the airline had not used them simply because it was not aware it held them.

“When we put together the merger [with US Airways], our process for accounting slots was extremely manual and we had the wrong count. There’s no good reason [for this underutilisation] and I'm a little beside myself that it happened. It was for the worst of reasons, it makes us sound completely ridiculous," Raja said during the hearing.

American Airlines justified its alliance with JetBlue, announced in mid-2020 and launched in February 2021, by the lack of opportunity to grow organically due to a lack of available slots. The US Department of Justice is trying to break up the partnership on competitive grounds.

"The [Northeast Alliance] eliminates competition between the largest airline in the world and a disruptive competitor on flights to and from Boston and New York. It deprives the public of the benefits the rivalry has brought to passengers for two decades," the administration argued in its lawsuit.

While Delta Air Lines (DL, Atlanta Hartsfield Jackson) is currently the single largest airline at JFK with a 28.1% market share, JetBlue Airways (the second largest carrier with a 27.8% share) and American Airlines (the third largest with 14%) collectively operate 41.8% of the scheduled weekly capacity at the hub, the ch-aviation capacities module shows.