US lifts nationwide ground stop for airports hours after halting all departures

The US Federal Aviation Administration (FAA) canceled a ground stop on all national flights hours after stopping departures at US airports on Friday.

Over 3,500 flights were canceled and over 10,000 flights within, into, or out of the United States were delayed, according to the FlightAware aviation tracker. With some 11,000 flights scheduled to depart from US airports after 4 p.m. local time (2200 UTC), more cancellations were expected, according to Cirium, an aviation analytics company.

What do we know so far?

"All departing traffic should remain groundstopped until further notice," the FAA said.

The agency said the ground stop is "due to extraordinary circumstances and reasons for safety." The FAA cited a temporary telecommunication outage and said, "Every flight has been accounted for and international flights will be handled on a case by case basis."

The agency said flights were halted "out of abundance of caution."

In a post on X, US Secretary of Transportation Sean Duffy said the stop was due to a communication issue impacting all Air Route Traffic Control Centers.

"FAA technicians are investigating the issue. We will provide immediate updates as we have them," he wrote.

US Homeland Security Secretary Markwayne Mullin told reporters at the White House that there was no indication this was an attack against the US.

"This is a telecommunications outage," Mullin said. "All the flights are accounted for."

"Everybody's safe. There's no reason to be concerned about your loved ones if they're flying," he said, adding, "There was no indication as of yet this was a nefarious attack."

The European Organisation for the Safety of Air Navigation, Eurocontrol, said all flights departing for US airports from its 42 member states were suspended following a request from the FAA to deal with technical issues.

Canada implementing 'traffic management' measures at major airports

Canada's air navigation service provider, NAV Canada, said it is closely monitoring the US ground stop and later said, "It was implementing traffic management measures at Toronto Pearson, Montreal-Trudeau, Calgary and Vancouver to safely manage traffic volumes."

"Travelers should expect delays and check with their airline. Our systems are operating normally," NAV Canada added.

Toronto Pearson Airport said flights between Toronto and the US have been impacted by the ground stop.

The FAA ground stop order came a day after Duffy asked Congress for $30 billion to upgrade and modernize the US Air Traffic Control System.

"This investment is critical to complete the modernization of our national airspace — delivering a resilient telecommunications backbone for air traffic controllers, modern hardware and software, state-of-the-art control towers, and world-class airport infrastructure," Duffy and Office of Management and Budget Director Russell Vought wrote in a letter to lawmakers.