The Federal Aviation Administration lifted a nationwide ground stop on Friday night after a communications failure disrupted air traffic control centers across the United States, grounding all departing flights for more than four hours and stranding hundreds of thousands of passengers.
The FAA ordered the halt just after 4 p.m. Eastern Time on Friday, citing "extraordinary circumstances and reasons of safety" after a telecommunications outage affected all Air Route Traffic Control Centers. The agency reopened US airspace at 8:15 p.m. Eastern Time, though officials warned that delays would continue into the weekend.
Transportation Secretary Sean Duffy said the outage stemmed from aging infrastructure, blaming hardware from the 1980s that became overloaded with data and crashed. He described the air traffic control system as "incredibly old" and said routers in the network were overwhelmed. Homeland Security Secretary Markwayne Mullin said the failure resulted from patching new technology into an existing framework, which caused the older system to become overwhelmed.
Investigators are examining whether a software update to the FAA's private communications network, operated by defense contractor L3Harris, triggered the crash. CBS News reported that the update caused the system to reboot and fail, a claim confirmed by multiple sources to the network. The FBI is probing whether the update went bad, according to Bloomberg.
The disruption canceled more than 6,600 flights and delayed over 10,000 others on Friday, according to flight-tracking data. Cirium estimated that 1.5 million people were stranded by the cancellations. International flights from Europe to the United States were temporarily suspended, and Canada halted flights to the US while offering assistance to the FAA. Passengers at airports including Chicago O'Hare and Atlanta's Hartsfield-Jackson were left waiting for hours, with some abandoning their trips entirely.
Mullin told reporters at the White House that there was no indication of a cyberattack or malicious activity. He ruled out any connection to this week's Microsoft outage or a new AI tool the FAA has been rolling out. "At this point, there is no indication that this is a malicious attack against us," he said. "Right now, this is just a telecommunications outage."
Some air traffic controllers disputed Duffy's explanation. Anna Giaritelli, a national security reporter for the Washington Examiner, told CNN she had spoken with 60 controllers and "none of them are buying what he said." She noted that the FAA typically performs system switches during midweek overnight hours when traffic is light, not during busy Friday afternoons.
The nationwide ground stop was only the second such order since the September 11, 2001, terrorist attacks. The previous one occurred in January 2023 when a pilot notification system failed, causing cascading cancellations for days.
Duffy used the incident to press Congress for funding to modernize the system. He said President Donald Trump had requested $30 billion for upgrades, but the administration needs $50 billion total. He warned that without new money, more disruptions would follow, though he said the system should return to normal before Thanksgiving travel on November 26.
