Southwest Airlines canceled hundreds of flights over the weekend, blaming the woes on air traffic control issues and weather.
The airline canceled more than 1,000 flights, or 29% of its schedule, as of 7 p.m. ET Sunday, according to flight tracker FlightAware.
"We experienced weather challenges in our Florida airports at the beginning of the weekend, challenges that were compounded by unexpected air traffic control issues in the same region, triggering delays and prompting significant cancellations for us beginning Friday evening," Southwest said in an emailed statement. "We’ve continued diligent work throughout the weekend to reset our operation with a focus on getting aircraft and Crews repositioned to take care of our Customers."
Southwest added that "frequencies between cities in our current schedule" makes restoring service more difficult.
"We’re offering Customers added flexibility to explore self-service rebooking options on Southwest.com, where they can get updates on the status of their travel," Southwest said, adding that it thanked customers for their patience.
The cancellations by Southwest mark the highest rate by far of the major U.S. airlines. Next in line was Allegiant, which canceled 6% of its flights. American Airlines canceled 5% of its flights, while Spirit canceled 4% on Sunday.
USA TODAY reported Sunday that the FAA said the weather and air traffic control issues were limited to Friday afternoon.
“Some airlines continue to experience scheduling challenges due to aircraft and crews being out of place,” the FAA statement read, according to USA TODAY. “Please contact the airlines for details about current flight schedules.”
The union representing Southwest pilots said in a Saturday statement that its members were not participating in "any official or unofficial job actions" and placed at least part of the blame on the airline.
"Our Pilots will continue to overcome SWA management’s poor planning, as well as any external operational challenges, and remain the most productive Pilots in the world," the statement read. "They will continue to be focused on their highest priority — safety. SWAPA Pilots are true professionals and will always maintain the highest level of responsibility to their crews, their passengers, and our airline."
Southwest did not immediately respond directly to union's statement.
Southwest was one of several airlines to announce last week it will require all workers to be vaccinated against the coronavirus or potentially lose their jobs. That mandate does not go into effect until Dec. 8.
A Sunday statement from the Southwest Airlines Pilots Association said, "SWA has claimed that the immediate causes of this weekend’s meltdown were staffing at Jacksonville Center and weather in the southeast U.S., but what was a minor temporary event for other carriers devastated Southwest Airlines because our operation has become brittle and subject to massive failures under the slightest pressure."