CHICAGO, IL – United Airlines experienced a system-wide technology failure on Wednesday evening, forcing the carrier to temporarily ground all of its mainline flights across the United States. The outage caused widespread travel disruption, leading to hundreds of flight delays and cancellations at major hubs.

The airline confirmed the ground stop was due to a "technology issue" and was not a cyberattack. The problem specifically affected the airline's Unimatic system, which manages critical flight information, including weight and balance calculations. As a result, the Federal Aviation Administration (FAA) issued ground stops for United flights at key airports, including Newark, San Francisco, Denver, Houston, and Chicago.

The issue, which began in the early evening, was resolved after a few hours, but United has warned that "residual delays" are expected to continue as the airline works to restore normal operations. According to flight-tracking websites, over 1,000 United flights were delayed on Wednesday, with dozens of cancellations.

Passengers took to social media to express their frustration, with many reporting being stranded on the tarmac for hours with little to no information. United has stated that it is treating the incident as a "controllable delay," meaning it will compensate customers for expenses like hotels where applicable.

This is the latest in a series of technical issues to hit the airline industry this year, following a similar IT outage that grounded all Alaska Airlines flights just a few weeks ago. The recurring problems are raising concerns about the resilience of airlines' technological infrastructure.

In other news, United recently announced the opening of a new 33,000 sq. ft. club at Denver International Airport, its fastest-growing hub. The airline also successfully completed a Department of Transportation review of its "Blue Sky" collaboration with JetBlue.