United Airlines said it has fixed a technology glitch that forced it to halt departures across the US, briefly crippling one of the nation’s biggest carriers on a busy travel day.

Federal Aviation Authority (FAA) officials said United crews had been unable to contact airline dispatchers through normal means.

“United asked the FAA to pause the airline’s departures nationwide,” the FAA said on Twitter, now known as X.

The FAA said the issue was limited to United and its subsidiaries.

It was less than an hour from the time the FAA issued a bulletin about United’s ground stop until the agency said flights were resuming — shortly before 2pm Eastern time on Tuesday.

“We have identified a fix for the technology issue and flights have resumed,” United said in a statement.

“We’re working with impacted customers to help them reach their destinations as soon as possible.”

United said earlier that it was “experiencing a systemwide technology issue” and was holding up all departing planes.

Flights already in the air when the technology problem happened continued to their destinations, the airline said.

By mid-afternoon on Tuesday on the East Coast, United had cancelled only seven flights, well below its average of about 16 per day over the busy Labour Day weekend, according to figures from tracking service FlightAware.

However, more than 300 United flights were delayed — 12% of the carrier’s schedule, far more than rivals American, Delta and Southwest — on a day that many holidaymakers were expected to fly home.

Transport secretary Pete Buttigieg, who has criticised airlines for flight problems and other issues over the past year, said the FAA was “receiving more information about the cause and scope of the issue, and DOT (the Department of Transportation) will make sure UA (United Airlines) meets its obligations to affected passengers”.

The FAA is part of the DOT.

Shares of Chicago-based United Airlines Holdings fell on news of the ground stop and were down almost 3% in afternoon trading.