A cyberattack hit the check-in systems at some European airports from Friday night, September 19, 2025, to Sunday, September 21, 2025. The attack caused long delays and many flight cancellations. Airports in Brussels, Berlin, and London were affected, but Brussels Airport was the hardest hit. Airport officials asked airlines to cancel about 140 flights on Monday, September 22, because the system was still unsafe. The system was made by Collins Aerospace, a company from the United States. The problem started when computers could not print boarding passes or bag tags or handle luggage. Airlines had to work by hand. Brussels Airport reported 25 canceled flights on Saturday, September 20, 2025, and 50 flights on Sunday, September 21, 2025.

The attack only affected the check-in desks. Online check-in, self-service machines, and air traffic control were not stopped. Staff gave passengers handwritten boarding passes and used laptops to help, but waiting times were very long. Experts said the attack could have been done by hackers, criminals, or even governments, but no one has admitted it. The European Commission said flight safety was not in danger. Collins Aerospace explained the problem was limited to check-in and baggage services, and it is still working to fix the system.