Aer Lingus Cancels 47 Flights After Security Breach—Widespread Disruptions Hit Dublin, London, Washington & More

Aer Lingus was forced to cancel 47 flights after a cyberattack struck its shared check-in and baggage management system, disrupting operations at Dublin Airport and several other major European hubs including London, Brussels, and Berlin. The incident began on September 19, 2025, and stemmed from a ransomware attack on Collins Aerospace’s ARINC cMUSE software, which is widely used for passenger processing by multiple airlines. As a result, thousands of passengers faced travel chaos with extensive delays, manual check-in procedures, and confusion across both short- and long-haul routes, notably impacting services to Dublin, London, and Washington.

During the disruption, airports had to revert to manual systems for tagging baggage and printing boarding passes, causing bottlenecks and long queues. At the peak of the crisis, some airports canceled up to half of their scheduled departures to manage congestion, and Aer Lingus reported it was “significantly impacted.” The cyberattack and related operational challenges spilled into the following week, as airline technical teams worked to restore digital services and passenger support, with the cloud-based recovery process still ongoing.

While normal check-in operations resumed at most affected airports by September 24, residual delays and intermittent manual workarounds continued as system security checks were finalized. Aviation cybersecurity experts have warned that such incidents are on the rise, emphasizing the vulnerability of airline operations to cyberthreats and the need for strengthened digital defences in global aviation.

Key Points:

• Aer Lingus canceled 47 flights after a ransomware cyberattack hit the ARINC cMUSE check-in system.
• Dublin, London, Brussels, and Berlin airports faced widespread delays as staff switched to manual operations.
• Manual processing caused extensive bottlenecks, flight cancellations, and passenger disruption for days.
• Full service was gradually restored, but airlines are urging travelers to check flight status and arrive early.
• Experts highlight growing aviation sector vulnerability following this and similar recent cyberattacks.