As airlines continue to grapple with the fallout from Friday’s global IT outage, thousands of flights have been canceled or delayed.
There were over 1,000 flights canceled and more than 2,300 delays as of 11 a.m. ET Sunday, according to flight-tracking website FlightAware. Delta and United Airlines have been hit the hardest with 539 and 254 cancellations so far, respectively. Endeavor Air, a wholly-owned regional subsidiary of Delta has also seen significant cancellations.
According to the Federal Aviation Administration, several U.S. carriers, including American Airlines, United Airlines, and Delta Air Lines, issued ground stops for all their flights early on Friday due to communication problems, which caused a domino effect into Sunday.
The cybersecurity firm Crowdstrike blamed the global tech outage on a defect in an update for Microsoft Windows hosts.
“Today was not a security or cyber incident. Our customers remain fully protected,” Crowdstrike CEO George Kurtz posted Friday on X.
The aviation sector was hit particularly hard due to its sensitivity to timings. Airlines rely on a closely coordinated schedule often run by air traffic control. Just one delay of a few minutes can throw off a flight schedule for take-offs and landings for an airport and airline for the rest of the day.
The FAA will issue ground stops and other precautionary flight control measures as needed, but most of the cancellations and delays Sunday are likely to be caused by airline crews and equipment being out of place.
“The airline industry is very thinly populated with planes. Once they’re out of place, they can’t run their normal playbook because their planes are not in place to run their route,” Jon Haass, a professor of cyber intelligence and security at Embry-Riddle Aeronautical University-Prescott, told USA TODAY on Saturday. “It’s not just one piece of software anymore, it’s an entire system.”
Travelers are advised to contact their airlines and monitor the FAA’s website for the latest information.