FAA nationwide ground stop: 10,543 delays, 3,580 cancellations

A single telecommunications outage halted every departure in the United States on Friday afternoon, and by evening the disruption had produced 10,543 flight delays and 3,580 cancellations, according to the tracking site FlightAware.

The US Federal Aviation Administration said in a statement that the nationwide halt to departures and delays to landings at all US airports, which began at about 4pm ET, was caused by "a temporary telecommunications outage." The agency offered no timetable for restoration.

"Every flight has been accounted for and international flights will be handled on a case by case basis," the FAA added.

The stoppage is rare. This is only the second nationwide ground stop covering all departures since the 9/11 attacks. The first came in January 2023, when the FAA paused all domestic departures for less than two hours.

Was this an attack?

Officials say no. Markwayne Mullin, the former Oklahoma senator now leading the Department of Homeland Security, told a news conference outside the White House: "there is no indication … that this was a neforous attack."

The FAA said the failure was a "temporary telecommunications outage." What caused that outage remains unclear. As of the latest updates, there is no sign the outage has been fixed, and no clear indication of how long the stoppage will last.

What happens to planes already in the air?

Mullin said the immediate priority is restoring communications so that all planes in the air can land safely. That framing matters. A ground stop does not order airborne aircraft out of the sky; it manages risk on the ground while controllers work through traffic already aloft.

What is a ground stop, exactly?

A ground-stop order by the FAA requires that aircraft remain on the ground and bars them from taking off. Planes already in the air are usually allowed to remain in the air.

The scale behind the order is large. The FAA has more than 14,000 air traffic controllers who handle the more than 44,000 flights that take off from airports across the US each day, according to FAA data. When communications fail across that system, the safest lever is to stop adding aircraft to it.

How big is the disruption?

FlightAware counted 10,543 flights delayed within, into or out of the US and 3,580 cancellations so far. Passengers at Boston Logan international airport watched departure and arrival boards as the agency issued the national ground stop "due to extraordinary circumstances and reasons for safety," following its earlier report of serious air traffic control communications issues.

International flights will be handled case by case, the FAA said — a signal that arriving long-haul traffic continues, but on a managed basis rather than a normal schedule.

What comes next?

The open questions are cause and duration. The FAA has not explained what failed in its telecommunications systems, and the Homeland Security secretary has ruled out an attack without offering an alternative explanation. Until communications are restored, the priority stated by Mullin is landing every aircraft safely, and the daily count of 44,000 departures will stay well below normal.