When an IT system attributed to Microsoft and CrowdStrike went down in the early morning of July 19, 2024, airlines were heavily affected. Although carriers are slowly coming back online, cancellations and delays are significantly mounting.

Frustrated flyers across the United States are slowly trying to get back in the air after a major IT outage forced airlines to ground hold all flights overnight.

CNN reports the outages affected everyone from airlines to hospitals and emergency response systems, leaving airlines to cancel flights and manually rebook flyers using hand-written boarding passes.

Over 2,500 Flights Cancelled, 8,300 Delayed After IT Outage

The outage is attributed to a CrowdStrike update deployed to Microsoft Windows-based platforms. According to CrowdStrike CEO George Kurtz, the issue was tracked down to a “defect found in a single content update for Windows hosts.”

As a result, airline systems were down for hours in the early hours of the day. All three of the legacy U.S. carriers – American Airlines, Delta Air Lines, and United Airlines – all requested ground holds from the Federal Aviation Administration until 9:00 AM or longer.

According to FlightAware.com, the outages resulted in 2,547 cancellations and 8,376 delays on flights within, into, or leaving the United States as of press time. Delts and United have been the hardest hit with cancellations. Delta was forced to cancel over 800 mainline flights and delay nearly 1,400, while United has cancelled 400 and delayed over 1,370 flights. American Airlines dropped 364 flights and delayed over 1,100.

Southwest Airlines, which experienced several major IT issues over the years, was minimally affected by the outage. The airline only cancelled four flights but was forced to delay nearly 1,100.

As a result of the turmoil, all of the major U.S. carriers are issuing travel waivers for flights departing on Friday, July 19. Delta warns that additional delays and cancellations could be expected “potentially through the weekend.” Media reports say flyers are left waiting in long lines at the airport waiting for rebooking assistance.

Keep up to date and get the latest information on the FlyerTalk forums. Individual experiences are being reported in the following threads:

American: CrowdStrike update and Systemwide IT issues on AA
Delta: IT Outage 7/18/24
United: Travel Waiver: Crowdstrike Outage 18 July –UA/AA/DL Groundstops, operations resuming

This is a developing story. Additional updates will be added when they become available.