More Southwest Airlines flights were canceled Monday following a weekend of service disruptions that left travelers stranded across the nation.
According to FlightAware's flight-tracking website, 363 Southwest flights were canceled, and 869 were delayed on Monday.
The Associated Press reported that the Dallas-based airline blamed weather and air traffic control issues for “operational challenges” that caused more than 1,900 flights to be canceled on Saturday and Sunday.
In a tweet, the Federal Aviation Administration countered those claims saying they have had no reports of traffic shortages since Friday.
The AP reported that the delays occurred shortly after Southwest's pilots union asked a federal court to block the airline’s order that all employees get vaccinated against COVID-19.
The Southwest Airlines Pilots Association rebutted claims that they were protesting, saying in a statement that they "can say with confidence that our pilots are not participating in any official or unofficial job actions."
"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," they said in a statement. "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."
Late Monday, Southwest attempted to explain what led to the cancellations.
"On Friday evening, the airline ended the day with numerous cancellations, primarily created by weather and other external constraints, which left aircraft and crews out of pre-planned positions to operate our schedule on Saturday. Unfortunately, the out-of-place aircraft and continued strain on our crew resources created additional cancellations across our point-to-point network that cascaded throughout the weekend and into Monday," Southwest said in a statement on its website.
Southwest also apologized to customers and employees.
"Southwest Airlines extends a tremendous apology to our customers and employees for the flight cancellations and delays which occurred over the weekend and on Monday."