The FAA nationwide ground stop was lifted on Friday evening after a communications failure at US air traffic control centres disrupted departures across the country. The four-hour grounding caused widespread cancellations and delays, with nearly 10,000 flights cancelled by 11:30 p.m. as airlines struggled to restore normal operations.
US Transportation Secretary Sean Duffy announced that American airspace had reopened at 8:15 p.m. Eastern Time (0115 GMT). However, he cautioned that lifting the restriction would not immediately clear the backlog of disrupted flights.
“It’s going to be slow,” Duffy told reporters at the White House.
According to flight-tracking website Flightradar24, Delta Air Lines and American Airlines had each cancelled more than 2,200 flights by 11:30 p.m. United Airlines had cancelled approximately 1,800. At some major airports, aircraft had reportedly been waiting more than five hours for gates.
Aviation analysts warned that the consequences could extend beyond Friday, with aircraft and crew schedules potentially taking several days to return to normal. Duffy estimated that tens of thousands of passengers had been stranded at airports across the United States.
The incident also brought renewed attention to the condition of the country’s ageing air traffic control infrastructure, including its communications equipment, technology and staffing levels.
FAA communications failure triggers nationwide flight grounding
Duffy said the technical problems began at 3:36 p.m. Eastern Time, when air traffic control centres experienced instability in their radar and communications systems.
The immediate issue involved network switches and routers that became overloaded with data. According to Duffy, this produced inconsistencies in the information being transmitted, prompting authorities to shut down the affected system.
He emphasised that the country had not completely lost radar or communications capabilities during the incident. Controllers were still able to land thousands of aircraft safely.
The immediate technical problem was subsequently resolved, and Duffy said that flying was safe. Nevertheless, the decision to halt departures demonstrated how problems within critical air traffic control systems can affect flight operations across the country.
Duffy and Homeland Security Secretary Markwayne Mullin met President Donald Trump in the Oval Office to discuss the outage.
Ageing US air traffic control system faces renewed scrutiny
The communications failure has intensified concerns about the resilience of US air traffic control infrastructure. The system has been affected by ageing technology, equipment and communications problems, alongside a shortage of several thousand air traffic controllers.
Duffy argued that replacing and modernising the existing infrastructure was necessary to reduce the likelihood of similar disruptions. He criticised Congress for not providing funding for a new system and called for $50 billion to modernise air traffic control.
He described the existing infrastructure as outdated and urged lawmakers to provide the funding needed for an overhaul.
The call came on the same Friday that the White House and the Department of Transportation had urged Congress to approve $30.1 billion for improvements to the country’s ageing airports and air traffic control infrastructure.
The two figures represent separate funding requests cited by the administration. Duffy’s $50 billion proposal was directed at air traffic control modernisation, while the earlier $30.1 billion request covered upgrades to airports and air traffic control infrastructure.
Investigation examines possible causes, including cyberattack
Authorities had not established the precise cause of the outage when the initial investigation was reported.
Mullin said there was “zero evidence” at that stage that a cyberattack or a rogue artificial intelligence system had caused the failure. Investigators had not, however, ruled out either possibility.
He described the incident as apparently “mechanically driven”, while stressing that the investigation was continuing. The National Security Agency was assisting the Department of Homeland Security with the inquiry.
The outage also appeared to involve a telecommunications network overseen by L3Harris Technologies, according to two airline officials. The network handles critical radio frequencies that air traffic controllers use to communicate with pilots.
L3Harris had not responded to a request for comment at the time of reporting. The available information did not establish whether a problem with the company’s network caused the wider system failure.
Passengers face disruption after FAA lifts ground stop
Reopening US airspace did not bring an immediate end to the disruption. Passengers at airports from Boston and New York to Seattle and Los Angeles continued to face cancellations, delays and disrupted connections.
Aircraft remained parked at gates, while crowded departure halls and airline service desks reflected the scale of the disruption. Thousands of travellers faced the prospect of spending the night at airports while waiting for replacement flights.
Edward Kargbo, 50, from West Chester, Pennsylvania, had been scheduled to travel on a 9 p.m. Ethiopian Airlines flight to Lomé, Togo. Instead, he expected to remain at the airport overnight before boarding a rescheduled flight at 6 a.m. on Saturday.
Louise Maher, 47, was also affected at Newark after her British Airways flight to London was disrupted.
The financial burden on passengers was another concern. According to the reported guidance, US airlines would not be required to compensate travellers for the disruption because the carriers were not responsible for the FAA system failure.
Airlines begin recovery operations as cancellations mount
Airlines faced the challenge of reorganising aircraft and crew schedules after the grounding. Even once departures were permitted to resume, the disruption to aircraft positioning and connecting services meant that restoring normal operations would take time.
American Airlines said it was prioritising international flights and services to smaller cities outside its major hubs. The aim was to position aircraft and crews in locations that would support a faster recovery.
The incident also had an immediate impact on airline shares. In after-hours trading, American Airlines, United Airlines and Delta Air Lines each fell between 1% and 2%. JetBlue Airways declined by approximately 3%, as investors assessed the potential financial consequences.
The cancellations were particularly significant given the rarity of nationwide flight ground stops in the United States. The only other nationwide grounding of domestic departures since the September 11, 2001, attacks occurred in January 2023, when the FAA halted departures for approximately 90 minutes.
The latest restriction lasted around four hours and affected flights across the country. Although the immediate technical problem was resolved, the resulting disruption highlighted the extent to which US aviation depends on reliable air traffic control communications and infrastructure.
Air traffic control modernisation remains a major challenge
The incident has placed the modernisation of US air traffic control systems back in focus. The immediate failure involved overloaded network equipment and inconsistent data, but the wider concerns extend to ageing technology, communications reliability and controller shortages.
The investigation will need to establish the precise technical cause and determine whether any external factors contributed to the outage. Meanwhile, the administration’s funding proposals underline the scale of investment it says is required to upgrade the country’s aviation infrastructure.
For airlines and passengers, the priority is restoring disrupted schedules. For aviation authorities and lawmakers, the longer-term challenge is improving the resilience of the systems that coordinate aircraft movements across US airspace.
