Due to the recent tech outages that affected global software, Delta Air Lines, among other airlines, has suffered from travel disruptions and flight cancellations.

“An airline is kind of like your circulatory system,” airline consultant Michael Boyd explained to CNN.

“If it stops, even for just a short time, the blood isn’t where it’s supposed to be,” Boyd continued. “Getting airplanes back to where they need to be, people where they need to be … all of that takes time. So even if it’s disrupted for only a few hours, it can take five times as long to make it right.”

The tech outage

According to The New York Times, over 500 Delta flights were canceled on Monday due to the outage. Over 1,300 flights were canceled by the airline on Sunday with another 1,600 delayed. Around 1,200 flights each were canceled on Friday and Saturday.

A video posted to Reddit showed passengers “strewn about” in the Atlanta airport.

The tech outage came from a faulty update to CrowdStrike’s software, which is used worldwide. Airlines were particularly affected by the disruption, including Delta Air Lines, United Airlines, Spirit Airlines, Allegiant Air and American Airlines.

CrowdStrike said Sunday that most of their affected computers are back online, per CNN. But complications remain as airlines try to get crews onto their proper flights.

Secretary of Transportation Pete Buttigieg said in a social media post that there have been “reports of continued disruptions and unacceptable customer service conditions at Delta Air Lines, including hundreds of complaints filed with @USDOT.”

“I have made clear to Delta that we will hold them to all applicable passenger protections,” he said.

Delta Air Lines CEO Ed Bastian gave an update to Delta customers on Sunday, saying that the pause in operation led to over 3,500 canceled flights through Saturday.

“The technology issue occurred on the busiest travel weekend of the summer, with our booked loads exceeding 90%, limiting our reaccommodation capabilities,” Bastian wrote.

“Specifically, the issue impacted the Microsoft Windows operating system,” he continued. “Delta has a significant number of applications that use that system, and in particular one of our crew tracking-related tools was affected and unable to effectively process the unprecedented number of changes triggered by the system shutdown. Our teams have been working around the clock to recover and restore full functionality.”

In the update, Bastian thanked Delta’s employees for their tireless work and told affected passengers that a travel waiver had been issued to allow them to change their itinerary as needed, free of charge.

According to CNBC, the event is similar to an issue Southwest Airlines faced at the end of 2022, when winter weather stranded millions of travelers.