The Federal Aviation Administration said Friday night that airplane departures could resume after lifting a nationwide ground stop that had halted flights across the United States earlier in the day. Officials cited "extraordinary circumstances" caused by communications problems at regional air traffic control centers, and the halt disrupted potentially thousands of planned flights and upended travel plans for passengers.

Homeland Security Secretary Markwayne Mullin told reporters at the White House that the introduction of some new technology into an old air traffic control system had overwhelmed it, and he could not rule out another outage. Trump administration officials blamed "overloaded" and "outdated" systems. Mullin said there were no "footprints" showing an attack and that the failure appeared to be "mechanically driven," though officials were still looking for the cause. There was no indication the communications failure was related to a cyberattack.S1S2

The ground stop was the first nationwide halt since January 2023, when a key FAA computer system malfunctioned, and the second since the aftermath of the Sept. 11, 2001, attacks. At least 827 flights were diverted as of 7:05 p.m. EST, with 670 sent back to their departure airports and 157 redirected elsewhere, according to the aviation analytics company Cirium. Washington Dulles International Airport, Los Angeles International Airport, Cincinnati/Northern Kentucky International Airport and Nashville International Airport were among the destinations where diverted flights ended up.S1

Even with the order lifted, airlines will not return to normal operations immediately because so many planes and crews are out of position. International flights were being handled case by case, with some seen taking off Friday evening. About 11,000 flights carrying more than 1.5 million passengers were scheduled to depart U.S. airports after 4 p.m. EST, raising the likelihood of further cancellations and diversions.S1S2