NEW YORK - US carrier United Airlines resumed flights late Wednesday, a few hours after a major computer system outage prompted the carrier to ground flights nationwide.

"The underlying technology issue has been resolved, and, while we expect residual delays, our team is working to restore our normal operations," the airline said in a statement.

The issue is related to a system that houses information about each flight, which is then fed into other systems, including those that calculate weight and balance and track flight times, it added.

Yet, the airline didn't say what caused the glitch.

The outage, beginning just after 6 pm Eastern time (2200 GMT), prompted ground stops at several major United Airlines hub airports, including Chicago, Houston, Denver, Newark and San Francisco, according to the US Federal Aviation Administration.

As of 10:25 pm ET (0225 GMT Thursday), flight tracking data from FlightAware showed that 1,038 or 34 percent of the airline's flights had been delayed on Wednesday.

United Airlines is not the first U.S. airline to suffer a technology issue. Delta Airlines cancelled hundreds of flights in the summer of 2024 due to a major system outage triggered by a faulty software update.