Airlines cancel more than 1,500 US flights

Massive flight cancellations have spilled over into a second day after thunderstorms pounded major airports on the East Coast on Thursday.

As of 9:30 p.m. ET Friday, flight tracking site FlightAware showed more than 1,500 flights in the United States had been canceled. Once again, New York's LaGuardia, Newark Liberty International and Reagan National Airport outside Washington were at the top for cancellations.

On Thursday, airlines canceled 1,248 flights nationwide, one of the worst days for flight cancellations of the past six weeks. Southwest Airlines canceled 370 flights, or 9% of its Thursday schedule. Southwest delayed another 1,800 flights, 46% of its Thursday schedule.

"We are working through a variety of weather-related challenges that are affecting a number of our larger operations across the country this week," Southwest Airlines said in a statement on Friday.

There were more than 7,700 reported delays in the United States on Friday, according to FlightAware.

Airlines have been struggling with flight cancellations and delays this summer as they face staffing shortages, severe weather and air traffic control delays.

US airlines have been preemptively trimming their schedules to ease air traffic disruptions, with American Airlines the latest to make cuts, particularly at its hub in Philadelphia.

American Airlines had canceled more than 200 flights by Friday afternoon.

Air traffic disruptions have been bad in Europe, too. London Heathrow and Amsterdam Schiphol airports announced moves this week to curb congestion. _Agencies