Ground stop lifted hours after stranding thousands of flights across the U.S.

A nationwide ground stop for departing U.S. flights was issued by the Federal Aviation Administration on Friday, lasting more than four hours and affecting thousands of travelers. The alert cited “extraordinary circumstances and for reasons of safety” and instructed that all departing traffic remain ground stopped until further notice.

The FAA lifted the ground stop at 8:15 p.m. ET after more than 7,000 flights were canceled and major airports reported large numbers of stranded passengers. Transportation Secretary Sean Duffy attributed the outage to an outdated air traffic control system and overloaded routers that caused instability in radar data and communications.

By Friday evening, several major carriers indicated they were resuming operations, with Delta Air Lines, United, and American among those reporting a return to service. Homeland Security officials said there was no sign of a cyberattack, and the public was not considered to be in danger.

At the time of the stop, more than 3,500 aircraft were in the air, and thousands of flights heading to U.S. destinations were affected as airports struggled with capacity and gate space. Officials described the situation as a result of decades-old legacy equipment, with renewed funding and upgrades already in the works but not yet in place.

Analysts and aviation experts noted the disruption could lead to knock-on delays as crews, planes, and schedules return to normal. Officials emphasized that safety procedures and redundancies help manage communications outages, though the event underscored ongoing challenges with the air traffic control system.

Airports such as Reagan National and Chicago O’Hare faced immediate congestion as the outage persisted, complicating taxiing, gate assignments, and potential diversions. By the night’s end, authorities cautioned that it would take time for airspace and operations to recover from the grounding.