A day after technological problems delayed hundreds of flights, operations appear to have returned to normal Monday for Southwest Airlines.
Southwest said that it was still working to get some delayed or displaced customers into open seats and to deliver baggage, but it expected the technical systems that run its customer service to perform normally.
The Dallas carrier had been warning passengers to arrive at the airport two hours early Monday and print boarding passes beforehand, but airline officials now say that travelers should expect a normal day.
Southwest suffered intermittent technical issues on its website, mobile app and in its phone centers and airports check-in systems Sunday. It was using backup systems to check-in travelers lacking printed or mobile boarding passes.
Airline representatives have not said what caused the problem, but did say there was no indication that hackers were involved.
There were about 500 delays out of 3,600 flights scheduled Sunday. Passengers reported long lines at several locations across the country, including major airports like Los Angeles International, which provided water and canopies to those stuck waiting in line outside.
On Monday morning, Baltimore-Washington International Thurgood Marshall Airport tweeted that operations were returning to normal with few delays and diminishing passenger lines.
Southwest is allowing traveling customers to change plans, as they had on Sunday, to accommodate any disruptions.