United Airlines suspended flights nationwide Wednesday night due to a problem with its weight and balance computer system, according to the airline, inconveniencing thousands of passengers.

According to the company, "Due to a technology issue, we are holding United's mainline flights at their departure airports."

At the airline's request, the Federal Aviation Administration (FAA) issued ground restrictions for all United flights at its major hubs, including Chicago, Houston, Denver, Newark, New Jersey, and San Francisco.

"We anticipate further flight delays tonight while we resolve this issue. Safety is our top priority, and we will work with our customers to get them to their destinations,” the airline stated.

This does not affect United's regional flights; additionally, it was clarified that flights already in the air will be able to continue to their destinations.

United passengers quickly took to social media to complain that they were stranded on planes grounded at the gate or on the tarmac. Other travelers arrived at their destinations only to find grounded planes blocking their arrival gates.

Some planes that were preparing for takeoff and waiting for the issues to be resolved eventually returned to their gates to deplane passengers.

United Airlines' impact is comparable only to that of Southwest Airlines in 2022, when it suffered a collapse during the busy holiday travel period. A severe winter storm caused travel disruptions across the United States, forcing airlines to cancel thousands of flights. While most recovered relatively quickly, Southwest did not. The airline ultimately canceled 16,900 flights, leaving more than 2 million passengers stranded.