This paper covers structural requirements for certification of a normal category plastic airplane. Due to the lack of service experience and published data, substantiation of the airframe requires special attention. Means for showing compliance with applicable regulations covering proof of structure, fabrication methods, protection of structure, material strength properties and design values, special factors, fatigue strength, and lightning protection are explained. By current standards, a plastic airframe is novel. However, plastics may be the answer to the corrosion and fatigue problems of metal aircraft.