Major airlines on Saturday canceled more than 4,000 US flights and delayed 3,000 more as the United States sought to recover from the longest nationwide shutdown of flights since the September 11, 2001, attacks.
The FAA on Friday issued a nationwide ground stop that halted nearly all departing flights for almost five hours due to a massive communications failure, which forced airlines to cancel nearly 10,000 flights and delay more than 7,000 others in one of the worst travel days in US history.
Transportation Secretary Sean Duffy said Saturday at a press conference that FAA contractor L3Harris was working at a very remote location to convert a location from cooper to fiber.
"We're working to determine was whether we had incompetence, meaning was it user error or installer error from L3Harris, or did they install a faulty router? We haven't determined what the fault was," Duffy said at a press conference.
The issue led to data overloading other communications centers. "We had over 1,000 connection attempts every four to five seconds, and what that did was gave us issues with our communication with airplanes, and it also caused some disruption with our radar," Duffy added.
Delta Air Lines, United Airlines and American Airlines all canceled about 20% of their flights Saturday, while JetBlue canceled 40%.
Duffy said an AI scheduling tool or cyberattacks were not to blame.
Though the FAA eventually lifted the ground stop on Friday night around 8:15 p.m. ET, the disruption for passengers was far from over, with tens of thousands of people still stranded at airports around the country. Airlines were trying to unclog airports and get flight crews and other personnel in position to recover from the massive disruption.
Many major airports said they could not handle any more diversions as they tried to get airplanes back in the sky. Many college football teams were stranded Friday and struggled to find ways to get to games Saturday.
American Airlines late on Friday said it was prioritizing flights to international destinations and to smaller cities outside its major hubs to position aircraft and crews for a faster recovery.
The FAA issued the ground stop because of an outage that appeared to be affecting a network that handles critical radio frequencies used by air traffic controllers to communicate with pilots, according to two airline officials.
The contractor that oversees the network, L3Harris, did not respond to a request for comment.
FUNDS SOUGHT TO FIX 'EMERGENCY'
Friday's problem is the latest and most dramatic sign of strain on a US air traffic control system beset by aging technology, equipment and communications problems and a shortage of several thousand controllers.
Transportation Secretary Sean Duffy on Friday called for $50 billion in funding to upgrade air traffic control systems, up from $30 billion he had sought earlier. "This is an emergency," he said.
Duffy said the trouble began at 3:36 p.m. ET (2036 GMT), when air traffic control centers experienced instability in radar and communications systems.
"Our switches, our routers actually got overloaded with data and they started to give us inconsistencies in the data from those routers and because of that we shut the system down," Duffy said, adding that air traffic personnel never completely lost radar or communications as they guided thousands of planes to landings.
Duffy said the immediate problem had been fixed and that flying was safe, but warned that a broader overhaul of the air traffic control system was needed to prevent similar failures.
Earlier on Friday, before the outage, the White House and Department of Transportation had urged Congress to approve $30.1 billion to upgrade aged airports and air traffic control infrastructure.
"What we have is an incredibly old air traffic control system," Duffy said. "Give us the money to fix it."
Homeland Security Secretary Markwayne Mullin said there was "zero evidence" so far that the outage resulted from a cyberattack or a rogue AI system, though investigators had not ruled out either possibility.
The National Security Agency was working with the Department of Homeland Security on the investigation, he added.
PAIN FOR PASSENGERS
From Boston to Seattle and New York to Los Angeles, passengers on Friday night crowded departure halls and airline desks as delays and cancellations mounted and aircraft remained parked at gates.
“I might cry at some point but not yet,” said Louise Maher, 47, who was stuck at Newark Liberty International Airport after the aviation meltdown disrupted her British Airways flight to London.
Because the FAA was responsible for the delays, airlines are not required to provide compensation to stranded passengers.
The only other nationwide ground stop since the September 11 attacks came in January 2023, when the FAA halted domestic departures for about 90 minutes.
Investors were already pricing in a financial hit to airlines. Shares of American, United and Delta fell between 1% and 2% in after-hours trading late Friday, while JetBlue Airways dropped about 3%.
Shares of L3Harris traded down about 3% after hours.
