This paper was presented at the Twentieth National Conference of the Society of Aeronautical Weight Engineers at Akron, Ohio, May 15 – 18, 1961. This paper discusses a method with which optimum aircraft configuration parameters can be identified. Aircraft performance is mainly affected by the wing parameters, wing loading, aspect and thickness ratio. Changing the wing shape and size will in turn affect; 1) Tail size, 2) Drag, 3) Useful load and/or gross weight. Weight and drag equations have been developed to be simultaneously used in aircraft performance analysis. Several typical examples are shown, the results of which are comparable to those optimization methods. These methods incorporate interrelated drag and weight effects. Design- point optimization of aircraft performance, wing shape and dimension can be quickly accomplished. The intent of this paper is to keep the designer from assigning arbitrary values to the principal parameters of a design. This is still frequently done, by referring to similar, known and built airplanes, or likewise, by looking at aircraft performance equation only. In other words, the performance of many present aircraft can still be improved by the awareness of engineers planning new aircraft designs.