The Curtiss-Wright CW-21, also known as the Demon, was an American fighter developed in the late 1930s as a lightweight, high-climb interceptor. The CW-21A was the initial variant, featuring a unique, slim fuselage and a retractable undercarriage that folded backward. The Demonstrator aircraft was famously used by Curtiss-Wright to prove the aircraft’s specialized role; it could out-climb contemporary fighters of the era, reaching 20,000 feet in under five minutes. This performance was achieved by sacrificing armor and self-sealing fuel tanks in favor of a high power-to-weight ratio.