US Flights Resume After Ground Stop, But Delays Are Still Expected
Caalamka
Air travel across the United States ground to a halt after a communications failure at air traffic control centres rippled through airports nationwide, prompting the US Federal Aviation Administration to order a rare countrywide grounding that was later lifted.
The ground stop became the longest US flight shutdown since the 11 September 2001 attacks.
US airspace reopened at 1.15am Irish time, but US Transportation Secretary Sean Duffy cautioned that departures would restart in stages and that carriers would need time to regain normal operations.
“It’s going to be slow,” Mr Duffy told reporters at the White House.
By 11:30pm, nearly 10,000 flights had been cancelled, including more than 2,200 each at Delta Air Lines and American Airlines, and 1,800 at United Airlines, according to Flightradar24.
The plane-tracking website said some aircraft at major airports had waited more than five hours for a gate.
Aviation analysts said the four-hour nationwide grounding could throw airline schedules off for days.
Planes wait on the tarmac at LaGuardia Airport, New York
Mr Duffy said tens of thousands of passengers were stranded at airports around the country.
He said he and Homeland Security Secretary Markwayne Mullin met with US President Donald Trump in the Oval Office to discuss the outage.
The breakdown delivered the latest — and most severe — warning about stress on the US air traffic control system, which has struggled with aging technology, equipment and communications issues, alongside a shortage of several thousand controllers.
Mr Duffy said the problem began at 3:36pm, when air traffic control centres 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,” Mr Duffy said, adding that at no stage did they completely lose radar or communications and they were able to safely land thousands of planes.
Mr Duffy said the immediate fault had been resolved and that flying was safe, while stressing that preventing repeat incidents would require a wider overhaul of the aging air traffic control network.
Passengers await updates at Orlando International Airport
Dublin Airport warned that flights between Ireland and the US could be affected this morning, with delays and a small number of cancellations.
Passengers were advised to contact their airline directly for the latest updates.
Mr Duffy accused Congress of failing to fund a replacement system he said could avert outages like this one, and said $50bn was needed to modernise it.
Earlier yesterday — before the outage — the White House and Department of Transportation had urged Congress to approve $30.1bn to upgrade the nation’s aging airports and air traffic control infrastructure.
“What we have is an incredibly old air traffic control system,” Mr Duffy said. “Give us the money to fix it.”
Sean Duffy addessing the White House Press briefing room last night
Homeland Security Secretary Mr Mullin said there was “zero evidence” so far that the outage resulted from a cyber attack or a rogue AI system, though investigators had not ruled out either possibility.
“It appears this was mechanically driven. However, we’re still looking,” Mr Mullin said.
He said the National Security Agency was working with the Department of Homeland Security on the investigation.
According to two airline officials, the outage appeared to involve a telecommunications network overseen by L3Harris Technologies.
The network carries critical radio frequencies used by air traffic controllers to communicate with pilots. L3Harris did not respond to a request for comment.
Queues at Charlotte Douglas International Airport in Charlotte, North Carolina
Even after the FAA lifted the ground stop, the headache for travellers continued. Passengers packed terminals and lined up at airline counters from Boston to Seattle and New York to Los Angeles as cancellations and delays piled up and planes sat idle at gates.
US airlines will not be required to provide compensation to stranded passengers because the carriers were not responsible for the FAA system failures.
The only other nationwide ground stop since the 11 September attacks came in January 2023, when the FAA halted domestic departures for about 90 minutes.
Markets quickly factored in the expected cost to airlines. In after-hours trading, shares of American, United and Delta fell between 1% and 2%, while JetBlue Airways dropped about 3%.
American Airlines said it was prioritising flights to international destinations and to smaller cities outside its major hubs to position aircraft and crews for a faster recovery.
