Flights were disrupted at Heathrow, Brussels and Berlin after a cyber‑related fault affected Collins Aerospace’s Muse system, which runs check‑in and boarding for several airlines. Collins Aerospace said it was working to restore the service, while Brussels Airport said only manual check‑in and boarding could proceed, with a significant impact on schedules. Berlin Airport reported longer waiting times at check‑in. Heathrow urged travellers to check with their airline before travelling and advised arriving no earlier than three hours before a long‑haul flight or two hours before a domestic one, with extra staff in check‑in areas to help minimise disruption.

At Heathrow, queues formed as passengers attempted manual check‑in. One traveller, a freelance journalist, arrived for a KLM service to Amsterdam that would connect to Cape Town, only to find digital boarding passes could not be issued and staff were processing checks slowly. The flight was due to depart while many passengers awaited check‑in, jeopardising onward connections.

Another passenger reported queuing for around three hours at baggage check‑in, with only two desks staffed and handwritten baggage tags used. She later learned the disruption was cyber related. Transport Secretary Heidi Alexander said she was monitoring the situation and urged travellers to check with their airline. Calum Miller, Liberal Democrat foreign affairs spokesperson, urged the government to state whether there is any suspicion of Russian involvement.