UPDATE: This story is no longer being updated. Read the latest on DIA delays here: Flight cancellations, delays continue at DIA Monday morning, with Delta leading the pack

More than 600 flights were canceled or delayed at Denver International Airport on Sunday as airlines continued to recover from a global technology outage that began Thursday.

There were 99 canceled flights and 508 delayed flights at DIA as of 4 p.m., according to flight tracking website FlightAware.

Of the 99 canceled flights, 65 were on United, 26 on Delta, seven on Frontier and two on American. Most of the delays were on Southwest, United and Frontier.

Thunderstorms in the area were also causing delays on arriving flights by an average of 40 minutes, according to the Federal Aviation Administration.

The initial outage caused more than 1,200 canceled and delayed flights at DIA on Friday and more than 800 on Saturday.

Updates from United, Frontier and Delta airlines posted Friday said the companies were recovering from the Crowdstrike software outage, which also impacted the Regional Transportation District, Colorado Division of Motor Vehicles and some police and fire agencies.

Some passengers reported airlines only offering flight credits to passengers whose flights were canceled because of the outage, Transportation Secretary Pete Buttigieg said in a post on X.

“Let me be clear — you are entitled to get your money back promptly if your flight is canceled and you don’t take a rebooking,” Buttigieg said. “If your airline is automatically giving you credits but you prefer cash, you can tell them you want a refund — and let us know if they fail to provide one.”

Passenger complaints can be filed with the Department of Transportation online.

This is a developing story and will be updated.

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Originally Published: July 21, 2024 at 10:38 a.m.