Britain's National Air Traffic Services said it had resolved a problem in its flight processing system in the evening but delays rippled across 15 U.K. airports and beyond as airlines and airports worked to clear a huge backlog of delayed flights.

Josie Donoghue spent three hours stuck on a plane at Gatwick before her Ryanair flight to Ireland was canceled.

"Getting through that airport was like trying to get out of Alcatraz," she said, referring to the notorious former island prison in San Francisco Bay. "It's just an absolute nightmare down there. It's the only word I can use to describe it."

Passengers at Gatwick Airport's South Terminal sit after flights were cancelled because of a technical issue in Britain's air traffic control system Tuesday, Sept. 8, 2026, in Crawley, south of London. Photo by AP

Departures at London Heathrow resumed but the busy airport suspended arrivals for the rest of the night because of the disruption and warned of further delays.