Flight cancellations continue Sunday as United, Delta struggle to recover from outage

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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.

Airlines rely on complex systems: Why the CrowdStrike hiccup could cause days of chaos

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.

Are flights still grounded? How long will flight delays last?

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.

How to find the reason for flight delay

Customers can ask airlines why their flight is canceled or delayed, but the Department of Transportation confirmed that it considers the delays and cancellations caused by Friday's IT outage to be "controllable" by the airlines. While airlines may say they didn't cause the computer error, it means that the DOT will hold them responsible for upholding the commitments they've made to customers when it comes to policies like rebooking or hotel and meal vouchers as the mess gets sorted out. Every airline's policy is outlined on the DOT customer service dashboard.

The Bureau of Transportation Statistics also tracks causes of delays and cancellations.

Airline waivers

Airlines are doing what they can to provide extra flexibility to those affected by the outage.

• Delta said in a statement that it was "continuing its operational recovery Saturday" and issued a waiver allowing all passengers traveling Friday to rebook their flights.
• United issued a waiver for select airports so passengers can make changes if their flights are affected, though a United spokesperson told USA TODAY that nearly all of the airline's flights depart or arrive in one of the airports covered by the waiver.
• Spirit issued a waiver allowing customers who are booked to fly Friday or Saturday through any airport in its network to change their flights at no additional charge.

What happens if my flight is canceled?

Department of Transportation rules require all airlines to offer customers a refund if their flights are canceled for any reason, but customers may be entitled to additional compensation if a cancellation is within the airline's control.

What should I do if my flight is delayed?

If your flight is experiencing a long delay, the Transportation Department suggests asking airline staff if they will pay for meals or a hotel room.

The DOT dashboard reflects airlines' official policies, but many carriers handle compensation for delays on a case-by-case basis and may provide vouchers or other benefits in some situations that are not formally covered.

What is considered a significant flight delay?

Each airline defines significant delays differently, but the DOT's dashboard identifies which airlines provide compensation for controllable delays of 3 or more hours.

For instance, all major U.S. carriers are supposed to provide a meal voucher for flights delayed by at least 3 hours for reasons within their control. Additionally, Alaska, JetBlue and Southwest offer credit or a travel voucher when a controllable delay "results in passenger waiting for 3 hours or more from the scheduled departure time," according to the dashboard.

How to file compensation for a delayed flight

Travelers seeking monetary compensation for delayed flights should file a claim with their respective airlines. Passengers seeking other types of compensation, like frequent flyer miles, may be able to request those through the airline's customer service.

This article originally appeared on USA TODAY: Flight cancellations continue Sunday as United, Delta struggle to recover from outage