At 8:15 pm Eastern time on Friday night, the FAA lifted the natiowide ground stop of US flights, according to a press briefing by DOT Secretary Sean Duffy.
"Right now it's going to be slow," Duffy said. "It depends on, do we have crews available? Do we have pilots and flight attendants? We will try to move as many as possible tonight. If not, we'll start tomorrow morning to move those aircraft, but it will take some time to unwind what happened this afternoon."
Duffy said that at 3:36 pm ET, "we experienced instability for our radar and our communications in our centers and our Tracons across the country," he said, referring to Terminal Radar Approach Control facilities. "There was inconsistency in the data from the radars and our communication with airplanes. … At that point we issued a ground stop, we had over 3,500 airplanes in the air."
"We didn't lose all telecom, but because of an abundance of caution, we issued the ground stop," he added.
Homeland Security Secretary Markwayne Mullin said in the same Friday press briefing that there was "no connection" to yesterday's global Microsoft outage. He added that "so far what we've seen, there is no cyberattack," he said.
As of 10:15pm Friday, there were 7,246 flight cancellations within, into or out of the US, according to aviation tracker FlightAware.
Original report below
The US Federal Aviation Administration has issued a nationwide ground stop for all US airports following communication issues impacting multiple air route traffic control centers, FAA said in a late Friday afternoon statement.
"FAA technicians are investigating the issue," it added. "We will provide updates."
In response to a request for comment, FAA directed BTN to Department of Transportation Secretary Sean Duffy's X account for updates.
The reason for the ground stop was "due to extraordinary circumstances and for reasons of safety" FAA said in a further statement it shared with CNN.
Air route traffic control centres are regional facilities that manage flights going across the country.
"Traffic should remain ground stopped until further notice," FAA said in an advisory according to CNN. "International flights will be managed on a case-by-case basis."