Hundreds of flights delayed after tech issue grounds United Airlines flights

CHICAGO -- A tech outage led United Airlines to ground flights nationwide Wednesday night, and even with the issue now resolved, over 1,000 flights have been delayed and dozens canceled.

The outage stemmed from an issue with the airline's weight and balance computer system, United said.

Find the latest info here:Ground stop lifted for United Airlines flights across the country after tech issue

"Due to a technology issue, we are holding United mainline flights at their departure airports," the airline said in a statement. "We expect additional flight delays this evening as we work through this issue. Safety is our top priority, and we'll work with our customers to get them to their destinations."

The airline said the outage began shortly after 6 p.m. ET and was resolved after a few hours.

Overall, more than 1,000 flights have been delayed and more than 40 canceled, according to FlightAware. United said it's covering meals and hotels for impacted customers.

The Federal Aviation Administration said in a statement it was aware the airline "experienced a technology issue disrupting their operations."

U.S. Transportation Secretary Sean Duffy said the issue was specific to United's operations "and is unrelated to the broader air traffic control system."

The airline confirmed in a statement to ABC News that the issue was not related to a cyberattack.

The ground stop did not affect United Express flights, and any flight that was already in the air will continue to its destination, according to the airline.

Multiple FAA notices stated that the airline requested ground stops at major hubs, including Newark, San Francisco, Chicago, Denver and Houston.

In Chicago, thousands of passengers packed onto United planes were stranded on the tarmac at O'Hare Airport.

'So we're all sitting there like sardines in this little airplane... haven't eaten, I'm hungry. Ten hours from Flint. I could have walked," United passenger Nancy Gonzalez said. "They're not responsible because it's a global computer glitch. Modern technology, supposed to make our lives simpler and easier and all it's done is frustrate me."

With full planes stuck at gates at the mercy of glitching technology, traffic backed up on runways and deep into O'Hare.

"We thought maybe they'd bring some stairs out, but they said they couldn't bring any of the planes out of the gates so we couldn't get into the gate," United passenger Joanne Delahan said.

ABC7 Chicago's Liz Nagy contributed to this report.