United Airlines ‘Technology Disruption’ Grounds Flights: What We Know

United Airlines suffered a major “technology disruption” on Wednesday night, the carrier has told Newsweek via email, leading to widespread travel chaos in the United States and beyond, and it later warned of “residual delays” even though the underlying issue had been resolved.

The carrier said airports affected by the technology disruption were: Denver; Newark, New Jersey; New York; Guam; Honolulu; Washington, D.C.; Houston; Los Angeles; Orlando, Florida; Chicago and San Francisco.

Further afield, it said flights at airports in Frankfurt and Munich in Germany and London were also affected. It gave no details.

Why It Matters

Complaints against U.S. airlines reached a record high in 2024 for the fourth time in the past five years, while flight cancellations and delays also got worse, according to a report released in May based on data from the U.S. Department of Transportation and the U.S. Bureau of Transportation Statistics.

U.S. airlines have been grappling with a host of issues that have led to delays over recent months, including air traffic control staff shortages, software glitches and bad weather, compounding public frustration.

What To Know

United Airlines said the problem, which began at 6.12 p.m. ET, was related to its Unimatic system that houses information about each flight which is then fed to other systems, including those that calculate weight and balance and track flight times, Reuters reported.

United said that the outage was unrelated to recent cybersecurity concerns in the airline industry.

“We are working with customers to get them to their destinations after a technology disruption on Wednesday evening. The underlying technology issue has been resolved, and, while we expect residual delays, our team is working to restore our normal operations,” the airline told Newsweek.

Full stops for United’s flights had been in place at airports including its hubs in Chicago, Denver, Houston, Newark and San Francisco, The New York Times reported, citing the (Federal Aviation Administration) FAA.

As of early Thursday, ET, tracking site Flight Aware reported delays at various airports including Denver, Newark, Washington, D.C., Houston, Orlando, Miami, Chicago, and Salt Lake City.

Hundreds of flights were delayed.

Transportation Secretary Sean Duffy said in a post on X, formerly Twitter, that the issue was specific to United’s operations, and was unrelated to the broader air traffic control system.

“We’ve offered full support to help address their flight backlog and remain in close contact with United,” the FAA said in a post on X.

Some frustrated passengers stuck on planes took to social media to vent.

“Everyone’s exhausted—passengers and @united staff. People are running out of phone battery, losing contact with family. This isn’t just poor service, it’s irresponsible. Let us off the plane!” wrote one X account, Allan Gallo.

What People Are Saying

The FAA posted on X on Wednesday: “We’re aware United experienced a technology issue disrupting their operations. Some delays may continue as they work through the recovery process. We’ve offered full support to help address their flight backlog and remain in close contact with United.”

Passenger Aaron Lassila wrote on X: “Totally unacceptable @united. Being stuck on a tarmac for 2+ hours with poor communication makes me question my loyalty all these years. Not the first time your systems have gone down, yet no contingency plan to get thousands of your customers off the tarmac?!”

Update 8/7/25, 2:55 a.m. ET: This article has been updated with additional information.