Major European airports are working to stabilize passenger processing after a cyberattack against Collins Aerospace’s MUSE check-in and boarding software triggered long queues, delays, and cancellations over the weekend. Heathrow, Brussels, and Berlin reported the heaviest disruption from late Friday, September 19, through Saturday, with recovery improving into Sunday but not yet complete. Brussels Airport warned of continuing schedule impacts and advised passengers to arrive early, while Berlin Brandenburg reported ongoing constraints and continued to use contingency procedures at its terminals. Airport operators stressed that the incident affected a vendor platform rather than airport safety systems or air traffic control. Collins and RTX have not publicly shared technical details beyond confirming the cyber incident.