United Airlines threatens to stop service at New York's JFK Airport unless federal regulators let it run more flights there

• United Airlines said it would halt operations at JFK Airport if it can't run more flights there.
• It had leased many of its slots to Delta Air Lines when it left JFK in 2015. It returned in 2021.

United Airlines said on Tuesday that it would drop its service at New York City's John F. Kennedy International Airport at the end of October if authorities don't grant it more slots to take off and land there.

United left JFK in 2015 to consolidate flights at its hub in Newark, New Jersey, but it decided to return in 2021. It now runs far fewer daily flights at JFK as it used to, as it had leased the rights for some of its slots to Delta Air Lines on its way out in 2015.

"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 in an email to employees on Tuesday, Reuters reported.

The email added that United had been urging the Federal Aviation Administration to allow it more runway slots "so that we can grow to be more competitive," the outlet reported.

United said that without that boost, it could not serve JFK "effectively compared to the larger schedules and more attractive flight times flown by our competitors" such as JetBlue Airways and American Airlines, Reuters reported.

The FAA uses flight slots to limit air traffic in hubs in order to prevent and reduce congestion.

United runs two daily flights between Los Angeles and JFK and two daily flights between JFK and San Francisco. According to Bloomberg, the airline said that ceasing this service "would obviously be a tough and frustrating step to take and one that we have worked really hard to prevent."

United said in the email that JFK's total flight capacity hadn't changed since 2008, even though the airport had since widened its runways and built multi-entrance taxiways, Bloomberg and Reuters reported.

In 2015, United leased at least 24 permanent flight slots at JFK to Delta when it shifted most of its operations from the airport to its hub in Newark, where United represents most of the air traffic.

United had also tried to obtain 24 slots from Delta at the Newark airport, but federal authorities blocked the trade out of concern that it would allow United to establish a monopoly on flights there.

Last year, United returned to JFK. Its CEO, Scott Kirby, has said the 2015 decision to leave the New York airport was a mistake.

According to Bloomberg, United said in its email that since many of its slots at JFK are leased to Delta, United has no access to them.

Delta and United did not immediately respond to Insider's requests for comment after business hours.

The FAA told Bloomberg in a statement that any flights added at JFK would be distributed "fairly" among airlines, adding that it "must consider airspace capacity and runway capacity to assess how changes would affect flights at nearby airports."

The FAA did not immediately respond to Insider's request for comment after business hours.