By Shivani Tanna and Rajesh Kumar Singh

CHICAGO (Reuters) -United Airlines said a technology issue that led to a grounding of its flights for a few hours at U.S. airports and major delays across its network on Wednesday had been resolved.

“While we expect residual delays, our team is working to restore our normal operations,” the airline said.

The technology issue prompted ground stops at several major United hub airports including Newark, Denver, Houston, and Chicago, according to the U.S. Federal Aviation Administration’s website.

United said the problem related to its Unimatic system that houses information about each flight that is then fed to other systems, including those that calculate weight and balance and track flight times.

As of 10:25 p.m. ET (0225 GMT on Thursday), flight tracking data from FlightAware showed that 1,038, or 34%, of United flights had been delayed on Wednesday.

The FAA acknowledged the technology issue and said that it has offered full support to help address United’s flight backlog.

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

United said it was treating the technology issue as a controllable delay, meaning it would pay customer expenses such as hotels when applicable.

The carrier’s problem came a few weeks after Alaska Airlines grounded all of its flights for about three hours due to an IT outage for the second time in just over a year.

In April 2024, Alaska grounded its entire fleet due to an issue with the system that calculates the weight and balance of its planes.

(Reporting by David Shepardson, Kanishka Singh and Jasper Ward in Washington, Shivani Tanna in Bengaluru and Rajesh Kumar Singh in Chicago; Editing by Sandra Maler and Jamie Freed)