U.S. flights were grounded or delayed on Wednesday as the Federal Aviation Administration (FAA) scrambled to fix a system outage, with passengers told to check with airlines for updates.
The FAA said it had ordered airlines to pause all domestic departures until 9 a.m. ET (1400 GMT) to allow the agency to validate the integrity of flight and safety information.
Flights already in the air were allowed to continue to their destinations.
The FAA said it was working to restore a system that alerts pilots to hazards and changes to airport facilities and procedures that had stopped processing updated information.
A total of 1,230 flights were delayed within, into or out of the United States as of 7.19 am ET (1219 GMT), flight tracking website FlightAware showed, without citing reasons. Another 103 within, into or out of the country were also canceled.
Shares of U.S. carriers fell in Wednesday’s premarket trading. Southwest Airlines was down 2.4%, while Delta Air Lines Inc, United Airlines and American Airlines were down about 1%.