In 2004 the FAA finalized the Sport Pilot/Light Sport Aircraft (LSA) category. This category of affordable aircraft makes owning an aircraft more accessible than ever. There are two airworthiness certification categories: 1A special light-sport aircraft (S-LSA), sold ready-to-fly that maybe used for flight training, rental, or personal flight, including personal flight instruction. 2An experimental light-sport aircraft (E-LS), sold in a kit form that may be used for personal recreational flight or personal flight training. This paper describes a design applicable to the first category: S-LSA. The aircraft will be primarily used for recreational purposes and a sport pilot may only operate this airplane during daylight hours. The occupants are seated in tandem. A three-surface design is chosen for its aerodynamic efficiency. The paper describes the design philosophy, design requirements, weight sizing, performance sizing, weight and balance, aerodynamics and stability and control. It shows the problems involved with designing a tandem seater airplane with enough visibility for both occupants.