An airliner is a passenger aircraft designed to carry many people safely across long distances. From a cyber-security view, it is a cyber-physical system: flight controls, communications, navigation, maintenance interfaces, power management, and onboard networks must all work together under tight safety rules.
Airliners matter because security failures are often about trust between subsystems, not one broken part. Attackers look for exposed maintenance ports, weakly segmented networks, insecure updates, or assumptions that one component can always trust another. Defenders reduce risk with isolation, strict access control, redundancy, configuration review, and testing in aircraft analogs or simulators before anything reaches service. In short, an airliner is a reminder that aviation security depends on managing complex dependencies as carefully as protecting software.