The Federal Aviation Administration lifted its nationwide halt of departing planes on Wednesday morning after a technology outage delayed thousands of flights, but airlines warned the issue will continue to disrupt travel throughout the day.
The FAA said early Wednesday domestic departures would be paused until at least 9 a.m. ET while the agency worked to restore the Notice to Air Missions System, which is responsible for sending messages to all pilots, such as closed runways, hazards and other information.
All flights currently in the air were safe to land, the agency said.
More than 5,400 U.S. flights were delayed as of 10 a.m. ET, according to flight-tracker FlightAware, and residual delays could last hours from the backup once the ground stop is lifted.
For example, Delta flights destined for Hartsfield-Jackson Atlanta International Airport, Boston and New York’s LaGuardia Airport, each were halted until 10 a.m. ET, the FAA posted on its website.
More than 800 U.S. flights were cancelled on Wednesday. More than 23,000 flights were scheduled to, from and within the U.S., according to aviation data firm Cirium.
“This technology issue is causing significant operational delays across the National Airspace System,” said Airlines for America, an industry group that represents major U.S. carriers, including Delta, American, United, Southwest and others.
The White House said Transportation Secretary Pete Buttigieg had briefed President Joe Biden on the outage.
“There is no evidence of a cyberattack at this point, but the President directed DOT to conduct a full investigation into the causes,” White House press secretary Karine Jean-Pierre said in a tweet.
The incident comes just weeks after bad weather during the busy holiday travel period prompted mass flight disruptions across the U.S. and days later, more than 15,000 Southwest flight cancellations after the carrier buckled from all the schedule changes.
Wednesday’s FAA issue added to concern from Washington, particularly about technology that the complex U.S. air system relies on.
“As the Committee prepares for FAA reauthorization legislation, we will be looking into what caused this outage and how redundancy plays a role in preventing future outages,” Sen. Maria Cantwell, (D-Wash.) chair of the Senate Commerce Committee, said in a statement Wednesday. “The public needs a resilient air transportation system.”
Southwest is preparing to cancel flights on Wednesday to avoid further disruption, Casey Murray, president of the Southwest Airlines Pilots Association, told CNBC.