United Airlines Tech Issue Grounds Hundreds of Flights. The Stock Shrugs.
Aug 07, 2025 05:13:00 -0400 by Callum Keown | #Airlines
United Airlines said the issue wasn’t related to cybersecurity. (Getty Images)
United Airlines grounded hundreds of flights due to a technology issue late Wednesday, causing delays and cancellations into Thursday morning.
“The underlying technology issue has been resolved, and, while we expect residual delays, our team is working to restore our normal operations,” United said in an emailed statement.
The problem was related to the company’s Unimatic system, which holds flight information and feeds it to other systems, including those tracking flight times and weight-and-balance data. The issue began just after 6.p.m Eastern time and was resolved within a few hours. The carrier said it wasn’t related to cybersecurity concerns.
More than 200 United flights were canceled Wednesday, while 1,083 flights—or 35% of its schedule, were delayed, according to data from flight tracker FlightAware. As of 4 a.m. Thursday, 114 flights had been canceled, or 3% of the carrier’s schedule, and 107 were delayed.
United Airlines stock appeared to be unaffected, pointing 0.1% higher in premarket trading.
Transportation Secretary Sean Duffy said the problem was “specific to United’s operations, and is unrelated to the broader air-traffic control system,” in a social-media post on X. He said he had been briefed by United CEO Scott Kirby.
It’s just the latest tech outage to affect the airline sector. Alaska Air temporarily grounded its entire fleet last month following an IT outage. Alaska said at the time that a critical piece of hardware at its data centers, manufactured by a third-party, unexpectedly failed.
Delta Air Lines is still seeking compensation from cybersecurity company CrowdStrike for the $500 million it said it lost last year following a major IT outage. CrowdStrike rejected Delta’s claims that it acted inappropriately and said it strongly rejects “any allegations that it was grossly negligent,” in a statement last year.
Write to Callum Keown at callum.keown@dowjones.com