FAA Lifts Nationwide Ground Stop After Halting More Than 11,000 US Flights

At 8.15 on Friday evening, Eastern Time, the Federal Aviation Administration reopened American airspace. The nationwide ground stop it had declared that afternoon had delayed or canceled more than 11,000 US flights, according to the tracker FlightAware, and had left airports in sudden disarray. The FAA confirmed the reopening in an advisory on its website.

Transportation Secretary Sean Duffy announced it plainly, and added a warning: it would take time to unwind what had happened that afternoon. He said the government had identified the problem that took down the air traffic control system, and that the system was operational again.

His explanation was technical. Duffy described an incredibly old system in which routers became overloaded with data and began returning inconsistent information. Because of that inconsistency, he said, the system was shut down. Earlier in the day, he had described the stoppage on social media as a communication issue affecting all Air Route Traffic Control Centers. The FAA's own notice said the ground stop was imposed due to extraordinary circumstances and for reasons of safety. According to CNN, the FAA told airlines the router malfunctions were believed to have started at Chicago Midway international airport and spread across the country. Duffy said more than 3,500 aircraft were in the air when the order came. A ground stop bars planes from taking off, while those already airborne are usually allowed to stay up.

Homeland Security Secretary Markwayne Mullin said preliminary investigations did not point to a nefarious attack. As of now, he told reporters, it was a telecommunications outage. The evening White House briefing with Duffy and Mullin quickly became a plea to Congress to fully fund a full build of a brand new air traffic control system.

The money is already part of the picture. Last year Congress approved $12.5bn to fix the FAA's ageing communications system, and on Friday the FAA and the White House asked for another $30.1bn to address other issues. Last week, the FAA had announced that the first digital air traffic control towers in the US were operational, in Alaska and Florida, part of a modernization effort meant to reduce delays and improve traffic flow.

The scale of the system explains the disruption. The FAA has more than 14,000 air traffic controllers handling more than 44,000 flights taking off across the US each day. This was only the third time all departing flights have been grounded nationwide: the first was on 9/11, and the second in January 2023, when domestic departures were paused for less than two hours after a pilot notification system failed.

As the reopening reached travelers, relief was uneven. At John F Kennedy airport in New York, a woman who gave her name only as Lola said she had already rebooked her flight to Atlanta for another day and was going home. "I don't like it," she said. JFK urged travelers to confirm flight status with their airline before heading to the airport, while San Francisco international said flights bound for Hawaii and Asia were cleared to depart. United, Delta, Southwest and American said they were resuming flights Friday night. United said that included some Friday night flights, and American said it would operate as many remaining flights as possible that evening.

The effects reached across the Atlantic. British Airways canceled a 10.30pm Heathrow flight to New York, and Manchester airport said three Virgin Atlantic US-bound flights due out Saturday morning were likely to be affected if the issue was not resolved soon.

Political criticism focused on communication. California governor Gavin Newsom wrote on X that Americans stuck at airports deserved answers, clear updates and a plan to get home, and faulted the administration for correcting reporters on AI's preferred name, a reference to Mullin's earlier exchange with a reporter. Congressman Ro Khanna told CNN he was still waiting for a congressional briefing and said hourly public updates would help give a sense of a timeline. The FAA said it thoroughly tested its systems for stability before clearing flights to resume. What remains to be seen is how long the backlog takes to clear and what Congress does with the funding request.