The Federal Aviation Administration issued the ground stop for all U.S. airports at about 4:11 p.m. Friday, Nov. 13, citing a "temporary telecommunications outage" that affected regional air traffic control centers. Officials described the order as a safety precaution. By 8:15 p.m., the agency had lifted the stop and reopened the airspace, federal officials announced at a press conference.

During the shutdown, nearly all departing flights were held on the ground. Some flights were cleared to take off, including those in Hawaii and Alaska airspace and some departing international flights. Inbound flights were allowed to land, and the FAA evaluated incoming international flights case by case.

Transportation Secretary Sean Duffy attributed the outage to a failure of "legacy" equipment and called on Congress to help replace the aging technology.

"We have old switches, old routers. We use 1980s little copper lines. It's an old system that went down. It went down everywhere. It got overloaded," Duffy said.

Homeland Security Secretary Markwayne Mullin said the disruption was not connected to a widespread Microsoft Outlook outage that affected people and businesses worldwide the day before. Federal officials said the public was never in danger and that all flights were accounted for.

"We have seen zero evidence that this was a cyberattack, or a SI attack," Mullin said. Investigators were still looking into the outage to rule out any "nefarious activity."

Flight-tracking website FlightAware reported more than 10,000 delays "within, into, or out of the United States" on Friday.

General air travel resumed Friday night, but officials cautioned it would take "some time" to return to full capacity. Duffy said larger planes carrying significant numbers of passengers would be given priority over smaller aircraft. Officials said they expected operations to ramp back up as Thanksgiving travel approaches, though they did not provide a specific deadline for normal service to resume.

Both secretaries repeatedly pressed Congress to fund better air travel infrastructure to prevent future outages.

Government officials also encouraged professional sports teams to contact the FAA to schedule flights so they could keep their scheduled game times this weekend.

Nationwide ground stops are rare. Only two have been issued since the Sept. 11, 2001, terrorist attacks: one in January 2023, when a malfunctioning FAA computer system prompted a nationwide halt, and the one immediately after 9/11.

Travelers were urged to check their flight status directly with their airlines.