Alaska Airlines says it’s resumed flights after a nationwide ground stop due to a tech outage.

The Seattle-based carrier, which also operates Horizon Air and Hawaiian Airlines, said in a social media post at 3:24 a.m. EDT Friday that operations had been restored “after a significant IT outage resulted in a system-wide ground stop of flights for Alaska and Horizon.”

The ground stop was lifted at 11:30 p.m. Pacific time, the airline said, adding that it was “working to get our operations back on track as quickly and safely as possible.”

“Since this afternoon, we’ve had more than 229 flight cancellations. Additional flight disruptions are likely as we reposition aircraft and crews throughout our network,” the airline pointed out. 

Flight tracking website FlightAware said that, as of 5 a.m. EDT Friday, 256 Alaska Air flights had been canceled Thursday and Friday and 234 delayed. It wasn’t clear how many of the cancelations and delays came during the ground stop.

“We appreciate the patience of our guests whose travel plans have been disrupted. We’re working to get them to their destinations as quickly as we can,” the Alaska Airlines statement continued. “Before heading to the airport, we encourage flyers to check their flight status. A flexible travel policy is in place to support guests as operations return to normal following an IT outage.”

In an earlier statement to CBS News, the carrier didn’t elaborate on the nature of the tech outage. 

Ground stops are issued by the Federal Aviation Administration, often at the request of airlines. 

CBS News has reached out to the FAA for comment.

Alaska Airlines, one of the largest U.S. carriers, is primarily centered on the West Coast, but services 140 destinations worldwide, including 37 states and 12 countries, according to its website.  

Air travel in the U.S. has experienced some stresses as a result of the government shutdown that started at the beginning of the October, with shortages of air traffic controllers causing flight delays at several airports.