U.S. flights resumed Saturday after the Federal Aviation Administration halted departures across the country for more than four hours on Friday, a nationwide ground stop that left thousands of flights delayed or cancelled. The ground stop was lifted at 8:15 p.m. ET on Friday, but the disruption was expected to continue through the weekend. The FAA said in a post on X that the agency had lifted the ground stop and that some departures were resuming, adding that it had thoroughly tested its systems to confirm they were stable and reliable before clearing flights to resume.
By early Saturday, FlightAware counted more than 6,200 delays and more than 3,400 cancellations. Flightradar24 separately reported nearly 10,000 cancelled flights to and from U.S. airports through Saturday, with Delta Air Lines and American Airlines each cancelling more than 2,200 flights, United cancelling 1,800 and Southwest nearly 1,400. The FAA said it took the dramatic step of grounding flights from about 9pm UK time for reasons of safety under what it called extraordinary circumstances, and Transportation Secretary Sean Duffy said the order followed a communication issue affecting all Air Route Traffic Control Centers.S1S2
Sports teams were among the hardest hit. NBA and NHL teams struggled to reach their destinations in time for weekend games, and the University of Southern California women's basketball team, which was due in Greenville, South Carolina, on Friday ahead of a Sunday game against the Gamecocks, remained stuck in Los Angeles and planned to depart the next day. Duffy said college football teams on charter flights could receive priority and urged them to contact the FAA to schedule flight times. The Southeastern Conference said some games had been moved to Sunday.S1S2
The disruption came three days after a new AI-supported air traffic system, Strategic Management of Airspace, or SMART, was introduced at 22 air route traffic control centres on Tuesday. The platform brings together around 200 data streams covering flight paths, schedules and weather. Homeland Security Secretary Markwayne Mullin called the outdated air traffic control system a national security risk, and said there was no evidence of a cyberattack. Duffy said telecommunications routers had been overloaded with data and had gone down.S1S2
The effects reached beyond the United States. Passengers at London Heathrow faced cancellations on services including American Airlines to Dallas, United Airlines to Houston and a British Airways service to New York, while Manchester Airport warned that three US-bound Virgin Atlantic flights were likely to face slight delays and Edinburgh Airport reported delays to inbound and outbound US flights.S2
