Passengers walk through Terminal 5 of London Heathrow Airport after flights were cancelled because of a technical issue in Britain's air traffic control system Tuesday, Sept. 8, 2026, in London. (Ellie Crabbe/PA via AP)

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. (Jordan Pettitt/PA via AP)

Passengers at Gatwick Airport's South Terminal form a line after flights were cancelled on Tuesday, Sept. 8, 2026 because of a technical issue in Britain's air traffic control system, near Crawley, south of London. (Jordan Pettitt/PA via AP)