A cyber-attack on software used for airport check-in and baggage operations caused cascading delays across parts of Europe on Saturday, with Heathrow cautioning travelers about disruption as Brussels and Berlin experienced longer queues, manual procedures and some cancellations. The incident centered on Collins Aerospace’s shared-use “Muse” system, with the company acknowledging a cyber-related disruption while airlines and airports deployed workarounds to keep traffic moving.

Scope and Impact

Heathrow said a technical issue at a third-party supplier was affecting several airlines’ electronic check-in and baggage services, while flight trackers showed widespread delays through the day. Brussels reported that the outage would have a large impact on schedules, and Berlin warned of longer waits as passengers were processed manually at counters and gates.

Airports’ Emergency Measures

Heathrow deployed additional staff and urged travelers to verify flight status and not arrive excessively early, as some carriers switched to backup or manual systems to maintain departures. At Brussels, operators were instructed to cut a portion of flights over a defined period to ease bottlenecks, while Berlin and other hubs said teams were prioritizing connections and boarding flows.

On-the-Ground Experience

Passengers at Heathrow described multi-hour queues, manual bag-tagging and boarding pass glitches that forced returns from gates, while others reported crews pulling people forward to avoid missed flights. Individual travelers also recounted being stuck on stands and missing onward connections as staff reverted to phone-based verification and manual check-in.

The Dublin Factor and Regional Knock-ons

While similar software issues were noted regionally, Dublin separately evacuated Terminal 2 as a precaution before reopening, adding to day-of-travel strain for some passengers. Officials said flight operations would resume after the all-clear, even as minor delays persisted amid the broader European system disruption.

What We Know About the Attack

RTX confirmed awareness of a cyber-related disruption affecting select airports, saying the impact was limited to electronic check-in and baggage drop and could be mitigated with manual operations. Cyber experts said it was too early to attribute responsibility, noting that financially motivated ransomware remains a common threat vector even as state-linked actors can deploy similar tactics.