Travellers across the United States faced major disruption on Friday afternoon when the Federal Aviation Administration issued a rare nationwide ground stop, pausing all departing flights for both domestic and international services.

The order came after a widespread telecommunications outage. Homeland Security Secretary Markwayne Mullin told reporters there was no indication of anything nefarious behind the halt, describing it as a precautionary move. The FAA said every flight had been accounted for and that inbound international flights would be handled case by case. Transportation Secretary Sean Duffy confirmed the problem was a communication issue, with FAA technicians investigating.

The scale is significant. Aviation analytics firm Cirium counted 26,284 departures scheduled from the US on November 13. By 5:50 p.m. Eastern, around 600 flights had been diverted — roughly 83% of them returning to their origin airport — and 481 cancellations had already been logged, a figure expected to climb. More than 11,000 flights were still scheduled to depart after 4 p.m. Eastern.

Pilots already in the air were not affected: United Airlines, among the four biggest US carriers, confirmed that airborne flights would continue while new domestic departures were held until the FAA lifted the stop. Nationwide ground stops are unusual — the last one came in January 2023, when a computer outage knocked out the FAA's NOTAM pilot notification system.

If you are flying in, out of or within the US today, check your airline's app before heading to the airport, expect cascading delays and cancellations even after the stop is lifted, and know your rebooking options. Passengers on domestic US tickets generally have rights to rebooking on the same airline at no extra cost, though cash compensation is not guaranteed as it is in Europe. Travellers connecting through US hubs to other destinations should allow generous buffer time and consider contacting airlines proactively to secure alternate routings while availability lasts.

This story was reported by Condé Nast Traveler.