American Airlines says it's restored most of the affected flights after a technical glitch in the company's scheduling system reportedly forced the airline to drop thousands of trips this month.
More than 12,000 flights between Sunday and the end of July were wiped out on Friday night because they lacked either a captain, first officer or both, after pilots had changed their assigned trips, the Allied Pilots Association, the union that represents American Airlines pilots, told CNBC.
American Airlines said in an emailed statement that it had already "restored the vast majority of the affected trips and do not anticipate any operational impact because of this issue," including the July 4 holiday weekend. A spokesperson for American couldn't provide details about how many flights were either dropped or restored.
American Airlines confirmed the technical issue on its pilot trip trading system. The platform allows pilots to request to add, drop and swap certain trips, spokesperson Matt Miller said in an email.
"As a result of this technical glitch, certain trip trading transactions were able to be processed when it shouldn't have been permitted," the airline said. The airline did not respond to a follow-up question about whether the technical issue had been fixed.
A similar scheduling snafu in 2017 threatened the cancellation of 15,000 flights that December.
The glitch added to the busy holiday travel chaos. Travelers were already facing hundreds of canceled flights and a few thousand delays on Friday, just as they had in recent weeks. Experts attribute the wave of flight disruptions to a short supply of pilots and air-traffic controllers, in addition to high demand.
American's pilots have been pushing their employer to address aviators' punishing schedules during contract negotiations. Delta and Southwest Airlines pilots have picketed in recent weeks for higher pay and better schedules.
Earlier this week, Dennis Tajer, a pilot with American Airlines and the communications committee chairman for the Allied Pilots Association, blamed the recent surge in flight cancellations on airlines' poor scheduling practices. As airlines oversell tickets for some trips, Tajer suggested in an interview with CNBC that some pilots are being overworked and others are being underworked.