The Vortex Pirates aircraft design team has chronicled the weight considerations in the preliminary design of a low cost interceptor. The process began with the derivation of an initial sizing relationship based on weights of similar aircraft adjusted for payload, and continued through the structural design and weight validation. The potential benefits and limitations of active c.g. management were investigated for a small aircraft with cranked arrow wing that caused large movements in the aerodynamic center. Validated weights were then used to investigate the effects of weight on cost and performance, resulting in the establishment of linear relationships. These relationships should be confirmed with varying configurations and more detailed mass properties; however, they are believed to be of sufficient accuracy for conceptual design. While this study focused on high performance fighters in the less than 30,000 pound (13,636 kg) clean takeoff weight class, it should serve as a roadmap for weights engineers new to the conceptual design process.