United Airlines (UA, Chicago O'Hare) has threatened to leave New York JFK at the end of next month unless the FAA awards it permanent slots at the airport.

The carrier's management explained in an internal memo to staff that its current operations at JFK were based on temporary slots secured during the COVID-19 pandemic when airlines were cutting capacity.

"If our latest request [for slots] is approved and the Federal Aviation Administration (FAA) can offer United an interim multi-season allocation, we are prepared to expand and provide consumers a more competitive JFK offering. But if we are not able to get additional allocations for multiple seasons, we will need to suspend service at JFK, effective at the end of October," the airline said.

United Chief Executive Scott Kirby has urged acting FAA administrator Billy Nolen to review the current slot limits at JFK as, in the airline's view, the airport has ample unallocated capacity. JFK has been capped at 81 movements per hour since 2008, which is currently just two more than New York Newark, even though JFK has one parallel runway more.

"A comparison to Newark makes it clear that there is additional capacity at JFK, especially given the airport's current slot availability has not been reassessed since substantial improvements have been made to the airport," United argued.

United Airlines exited its JFK operations in 2015 to focus on Newark as its main hub for the New York metro area. The airline also continues to serve New York La Guardia but without a base at the airport. In 2020, Kirby said United would use the pandemic market reshuffle to "aggressively" return to JFK. The return materialised on February 1, 2021 but was based on temporary slots.

"Ever since we started flying our JFK routes in February 2021, our goal has been growth. During that time, we've made repeated requests to the FAA for permanent slots while also pursuing commercial agreements to acquire slots from other airlines - all in an effort to be more competitive at JFK. Unfortunately, we have not been successful in gaining additional permanent slots," the carrier said.

FAA said in a statement that any changes to the JFK capacity cap would have to be carefully assessed not just in light of the airport's infrastructure but also the impact on New York's congested airspace and other airports in the region. If and when the cap is increased, the regulator would then allocate the new slots to airlines based on a tested and transparent procedure.

The ch-aviation capacities module shows that United's presence at JFK is currently limited to 28 weekly departures, which amount to just a 0.7% market share at the airport by scheduled capacity. United thus trails not just market leaders Delta Air Lines (27.8% market share by capacity), JetBlue Airways (27.5%), and American Airlines (13.9%), but also numerous foreign carriers that serve JFK.