LONDON (AP) — An air traffic control problem disrupted travel across Britain on Tuesday, canceling more than 1,000 flights and leaving passengers stranded for hours on airport runways and in terminals, according to flight-tracking website Flightradar24.

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.”

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.

Passengers on a British Airways flight that had been due to fly to Baltimore disembarked after four hours on the ground at Heathrow. During the long delay, flight attendants served pasta and chicken curry while patient passengers watched movies or strolled up and down the aisles.

But passengers then learned their problems were far from over. There was mayhem at the baggage claim area and they were told no one could help them and to file claims for their bags.

British Airways said it was forced to cancel or divert more than 100 flights. Ryanair said more than 65,000 of its passengers had been disrupted and it had canceled more than 50 scheduled flights.

“The severity of the issue means there will be a significant knock-on impact,” a British Airways spokesperson said. “This incident was entirely out of our control and incredibly frustrating for our customers and colleagues, with aircraft and crews ending up out of place.”

Some passengers took to social media to complain about being stuck on planes for hours and expressed frustration about a lack of communication from airlines.

Affected airports included Stansted and City in London, as well as those in Manchester, Birmingham, Gatwick and Scotland. They warned passengers to check the status of their flight with their airline.

Budget airline EasyJet said some of its flights were “unable to operate” and that the system failure caused “delays to flights across Europe.”

The Associated Press