Spirit Airlines canceled more than half of its flights Wednesday and apologized to customers for severe disruptions in recent days.
The union representing Spirit's flight attendants said the company was addressing the meltdown by using procedures developed to recover from hurricanes.
Aviation industry officials said the busy summer travel season, combined with lingering impacts of the coronavirus pandemic, have complicated airline scheduling and added to logistical problems. Spirit faced its own serious set of problems.
Spirit canceled more than 800 flights over two days, including 61 percent of its flights Tuesday, according to aviation data firm FlightAware.
The airline said many of those cancellations were part of a "thorough reboot of the network, allowing us to reassign our crews more efficiently and restore the network faster."
The company blamed "overlapping operational challenges" for the problems. It said a combination of bad weather, computer problems and staffing shortages had caused "widespread irregularities," issues exacerbated by high numbers of summer travelers and fuller flights industry-wide.
The Association of Flight Attendants-CWA said Spirit had an IT outage Tuesday that prevented employees from using the crew scheduling system for more than an hour, compounding other challenges and stymieing efforts to rearrange flight plans for flight attendants.
American Airlines had significant cancellations earlier this week following summer storms at its Dallas-Fort Worth International Airport hub.
"It was sustained wind, hail and rain. It was not a great situation for the operation," said American spokesman Curtis Blessing. "The result of that has been weather recovery for the last couple days."
Scores of diverted planes Sunday left crews out of position, he said, leaving lingering effects. "We're coming out of it," Blessing said.
FlightAware data indicates American canceled 377 flights, or 12 percent of its total, on Tuesday. On Wednesday, it canceled 100 flights.
The TSA said it screened 1,797,120 people Tuesday, compared with 543,601 that day last year and 2,387,115 in 2019.