FAA Ends Nationwide Flight Ground Stop After Four-Hour Outage

The stoppage lasted more than four hours and was the longest nationwide grounding since the September 11, 2001 attacks. More than 8,500 flights were delayed and nearly 8,000 cancelled on Friday, according to FlightAware. When the FAA announced the stop, more than 3,500 aircraft were already airborne; some diverted while others continued to their destinations.

The FAA began allowing departures again during the evening, with flights at San Francisco International Airport among those cleared earlier. The disruption also halted US-bound flights from Eurocontrol member states and Sydney, while Air Canada cancelled service between Canada and the United States. At Dallas Fort Worth International Airport, passengers faced long lines as they tried to rearrange travel after the stop ended.

Transportation Secretary Sean Duffy said an overloaded legacy communications system had failed, affecting air traffic communications and radar. He said newer technology added to the older system had contributed to the overload and estimated a full overhaul would cost $50 billion. Homeland Security Secretary Markwayne Mullin said officials had found no evidence of a cyberattack and ruled out a connection to the Microsoft outage that began Thursday. Both said passengers had not been in danger.

Duffy warned that the disruption would take several days to unwind, with tens of thousands of travelers stranded at airports. JetBlue cancelled its remaining domestic flights Friday evening, while Delta said it was resuming operations. The outage exceeded a 2023 nationwide grounding that lasted one hour and 52 minutes after a failure in the system used to publish air safety notices.