Technical glitches that delayed hundreds of flights on Sunday could affect today’s flights as well.

By Tom Huddleston, Jr. /
October 12, 2015
© 2011 Southwest Airlines Co.
| Credit: © 2011 Southwest Airlines Co.

Passengers trying to fly with Southwest Airlines are reportedly still experiencing delays Monday morning following the Dallas-based airline’s earlier warning that “technology challenges” could delay the check-in process over the weekend.

Technical problems delayed roughly 450 of the 3,600 Southwest Airlines flights scheduled for Sunday, when the airline warned customers that it was relying on back-up computer systems to check-in passengers around the country. Southwest urged customers traveling Sunday evening or Monday to go online to check-in for their flights and print boarding passes before heading to the airport. The airline also suggested that passengers arrive at the airport at least two hours ahead of their flight departure time.

In a statement posted to the airline’s website and updated Sunday evening, Southwest warned passengers of continuing problems with the company’s systems. “Intermittent performance issues continue impacting our in-airport Customer Service technology systems and across our online platforms (, Southwest Mobile App and site),” the company said.

Southwest has yet to state publicly what caused the glitch or how long it will be before it is resolved, though a company spokesman told CBS News that the airline had seen no evidence of any hacking.

Delays on Sunday led to reports of exceptionally long wait times at airports around the country, with images of massive airport lines making the rounds on social media:

This story originally appeared on Fortune