US Flight Disruptions Stretch Into Sunday After Nationwide Ground Stop

Thousands of flights across the United States were cancelled or delayed on Sunday, as the country's air traffic control system continued to recover from a technical failure that triggered a rare nationwide ground stop two days earlier.

More than 5,000 flights were delayed and about 2,000 were cancelled during the day. Secretary of Transportation Sean Duffy said normal operations may not be restored until Monday. "We have airplanes and crews that are out of position, so it takes a little bit of time," he told the BBC's US partner CBS.

The disruption began on Friday, when the Federal Aviation Administration announced at 15:54 EST (20:54 GMT) that all aircraft scheduled to depart the US would be grounded until further notice. More than 3,500 airplanes were in the air at the time. Some were diverted to other airports, while others flew on to their destinations.

In the aftermath, 8,500 flights were delayed and another 8,000 cancelled, according to tracking service FlightAware. The stoppage left passengers stuck inside planes on the tarmac, unable to take off or return to their gates, while others were stranded in airports, sleeping on the floor and desperately trying to reach their airline. The grounding also had an impact on schedules around the world, with some flights out of the UK and Europe cancelled.

The ground stop was lifted after about four and a half hours, but the impacts continued through the weekend. On Saturday, airlines cancelled more than 5,900 flights, and more than 7,000 others were delayed.

Investigators are still working to determine the root cause of the failure and who is at fault. Duffy said the administration decided to ground flights after failures in a key system that allows air traffic controllers and pilots to communicate.

The transport secretary said a computer router installed as part of an upgrade from copper wire to fibre started sending out faulty signals. The router, a piece of equipment that directs traffic across the network, was installed in El Dorado, Arkansas, and "flooded our network", he said on Sunday.

Duffy said issues will continue to arise until the US makes major modernising changes to its air control system, which he said needs a complete overhaul. "Let's not lie to each other," he said on NBC's Meet The Press. "We have to make investments into a network that has been neglected for decades."

President Donald Trump also urged Congress on Sunday to approve more money to modernise the system. In a post on Truth Social, he said "we can get it built quickly and efficiently" and promised it would be the best system anywhere in the world. Much of the current air control system is 50 years old, he said, adding that the work should be done "all at once, not in drips and drabs".

Experts say the US uses antiquated technology for flight communications. Aviation analyst Miles O'Brien described the system as "a house that's about to be condemned". He told the BBC it is "a system in the United States that we have allowed to decay", adding: "It is worse than a fixer-upper."