A serious failure in the US Federal Aviation Administration's communications systems caused thousands of flight cancellations and delays after the agency ordered a nationwide suspension of departures.
The ground stop was lifted after several hours, although restoring airline schedules was expected to take days.
The disruption began on Friday 13 November 2026, when a technical fault affecting air traffic control centres prompted the FAA to halt departures across the United States.
The order applied at airports nationwide. Aircraft on the ground were not permitted to take off, while those already airborne could land safely.
According to Reuters, more than 6,600 flights were cancelled and a further 8,600 delayed, causing major disruption for passengers and airlines. Hundreds of aircraft also had to return to their departure airports or divert elsewhere.
What caused the nationwide ground stop
US Transportation Secretary Sean Duffy said the problem began when communications and data transmission systems became unstable, affecting the operation of air traffic control centres.
Initial technical assessments suggested that overloaded network equipment had disrupted the handling of information used by controllers to track flights.
US authorities said there was no evidence at that stage of a cyberattack or other malicious action. The exact causes remained under investigation.
The incident has revived debate about ageing US air traffic control systems, which have faced infrastructure problems for years and require extensive modernisation.
Departures resume, but delays continue
The FAA announced that it was lifting the nationwide ground stop at 8.15pm on Friday, US Eastern time — 3.15am on Saturday in Greece — allowing departures to resume gradually.
A rapid return to normal was not expected, however, because large numbers of aircraft and crews were out of position across airline networks.
The disruption also affected international air connections. Airlines warned that delays and cancellations could continue over the weekend.
It was the first nationwide suspension of US departures since January 2023, when a technical problem in the system providing notices to pilots caused similar disruption.
The latest incident highlights the serious consequences a technical failure can have for critical infrastructure, particularly in one of the world's largest and busiest aviation networks.
