Do airliners have keys?
Keys are not required to start an airliner’s engine, nor are they needed to open aircraft doors. Only small airplanes, like a Cessna, require keys and the only key I have is for the aircraft’s medical kit. Instead, switches and levers in the cockpit start the engines using compressed air, supplied by the Auxiliary Power Unit (APU), a small gas turbine engine located in the aircraft’s tail. Exception: In the Boeing 787 I fly, engines are started electrically without compressed air from the APU.