US lifts nationwide flight suspension after air traffic system outage

The United States lifted a nationwide ground stop at its airports after an hours-long disruption to the air traffic control system, which officials attributed to outdated communications equipment.

The Federal Aviation Administration (FAA) lifted the suspension after around four hours on Friday, allowing flights to resume across the country. However, Transportation Secretary Sean Duffy warned that it would take time for air traffic operations to return to normal.

The disruption led to nearly 6,000 flight cancellations, according to flight-tracking service FlightAware, leaving hundreds of thousands of passengers stranded and disrupting domestic and international travel.

Duffy said outdated switches, routers and ageing copper communication lines had become overloaded, causing a widespread system failure.

“Our switches, our routers actually got overloaded with data, and they went down,” he said during a White House briefing, reiterating the need to modernise the country’s air traffic control infrastructure.

The disruption came a day after the administration sought $30.1 billion from Congress to upgrade and modernise the US air traffic control system.

Homeland Security Secretary Markwayne Mullin ruled out a cyberattack or any connection with the recent Microsoft service outage, saying authorities had found no evidence of hostile activity. He added that security and law enforcement agencies were continuing their assessment.

The ground stop caused widespread confusion at airports, with passengers reporting repeated flight delays, cancellations and limited information about departures. Some travellers were asked to leave aircraft shortly before take-off.

A nationwide flight suspension is highly unusual in the United States. A similar ground stop was imposed in January 2023 following a failure of the pilot notification system. The only other nationwide suspension occurred after the September 11, 2001 attacks.