Southwest Airlines said that about 800 of its 3,355 scheduled flights were delayed at least 15 minutes Sunday. Passengers reported long lines at several airports and in Los Angeles, airport workers handed out water and provided shade canopies to travelers stuck in lines outside the terminal.
Brad Hawkins, a spokesman for Southwest, said workers fixed a failed software application that had caused the problems. He did not provide more details or describe but said there was no indication that hackers were the blame.