• Spirit has canceled hundreds of flights since Sunday.
• Weather, technical problems and staff shortages contributed to the disruptions.
• The carrier vowed to improve its operations by learning from the meltdown.

Spirit Airlines canceled more than half of its flights on Wednesday, in an effort to "reboot" its operations after a wave of disruptions that started over the weekend due to a mix of bad weather, staffing shortages and technology problems.

Spirit has canceled more than 1,000 flights since Sunday and hundreds more were delayed.

Furious customers complained on social media about the cancellations and difficulty reaching customer service agents. Some tweeted images of long lines at airports and travelers lying on the floor near gates.

The chaos is a major test for Spirit's executives who have worked in recent years to improve the airline's reliability and customer service.

Spirit said the disruptions were "exacerbated" by the surge in summer travel, which rebounded from the coronavirus pandemic faster than airline executives expected.  Fuller flights mean fewer options to rebook guests, the carrier said.

"The last three days were extremely difficult for our Guests and Team Members, and for that we sincerely apologize," Spirit said in a statement.

More than 400 flights, 60% of the day's schedule, were canceled Wednesday, according to flight tracking site FlightAware.

Airlines sometimes scrub large numbers of flights to avoid further disruptions and get employees and planes into the right place to resume flights.

Spirit said it expects cancellations to "progressively drop" in the days to come.

American Airlines this week also canceled hundreds of flights after hours of severe weather that included high winds, lightning and hail hit Dallas/Fort Worth International Airport, its largest hub.

On Wednesday, American's operation stabilized with about 100 cancellations, roughly 3% of the day's schedule, down from 12% of canceled flights on Tuesday.

American has been confirming seats for flight attendants on board, instead of the usual practice of having them fly standby or in jump seats, for their commutes to ensure they get to their stations on time, a spokeswoman said.

Spirit said it would learn from the meltdown.

"By taking an in-depth look at the challenges we're facing, we have identified opportunities for improvement that will help us operate a more resilient network and better serve our Guests," it said in a statement.

Thunderstorms complicated Spirit's efforts to recalibrate on Wednesday. Gate and taxi delays at Spirit's main base in Fort Lauderdale, Florida, were more than an hour in the morning but lessened during the day, according to the Federal Aviation Administration.