More than 11,000 flights disrupted as an outage exposes weaknesses in ageing US aviation infrastructure; authorities rule out an immediate threat of a cyberattack
The United States lifted a nationwide flight ground stop on Friday after a communications failure disrupted air traffic control operations, affecting more than 11,000 flights and leaving thousands of passengers stranded at airports.
The Federal Aviation Administration (FAA) ordered the restrictions, citing safety concerns after communications problems affected regional air traffic control centres. The shutdown lasted more than four hours, marking the longest nationwide disruption of its kind since the September 11, 2001, terrorist attacks.
US Homeland Security Secretary Markwayne Mullin said the disruption was caused by a telecommunications outage involving new technology introduced into an ageing air traffic control system. He said there was no immediate indication of a malicious attack.
“This isn’t another 9/11,” Mullin said, assuring the public that all aircraft already in the air had been accounted for and that there was no reason to fear for passengers’ safety.
The ground stop began at 3.54 pm Eastern Time on Friday, preventing aircraft on the ground from taking off while allowing planes already airborne to continue to their destinations. Emergency medical and law enforcement flights were permitted to operate.
According to flight-tracking service FlightAware, around 15,000 flights were delayed or cancelled. At least 827 aircraft were diverted, including several sent back to their original departure airports, according to aviation analytics firm Cirium
Major airports, including Washington Dulles, Los Angeles International, Cincinnati/Northern Kentucky and Nashville, received diverted aircraft. The disruption also affected international services, with airlines in Canada and Europe adjusting or cancelling flights.
US Transportation Secretary Sean Duffy said ageing telecommunications equipment, including overloaded switches and routers, contributed to the failure. He stressed that the country had not lost all radar capabilities but that the restrictions were imposed as a precaution.
President Donald Trump said the incident did not appear to involve a cyberattack or artificial intelligence. Investigators are examining possible links with the FAA’s introduction of an AI-powered system designed to identify problems and suggest alternative flight routes.
Although departures have resumed, authorities warned that delays and cancellations could continue as airlines work through the backlog. The incident has renewed calls for modernising the country’s ageing air traffic control infrastructure.
