Aircraft design is still a complex engineering process and many decisions are made based upon qualitative choice of the designer. The use of genetic algorithm (GA) as design and optimization methodology for Aircraft can help to reduce the number of qualitative decisions. The Fajr is a super short takeoff (T.O.) and landing (SSTOL) Aircraft, which is designed to fulfill the desire for new short runways such as heliports, center-city-to-center-city travel and carrier on-board delivery (COD) military Aircraft. The objective function for the optimization was a minimization of life-cycle-cost (LCC). Results of the design methodology are discussed, which shows the ability of the GA to perform Aircraft conceptual design. In this approach best SSTOL Aircraft configuration of word, such as a Boeing YC-14 and QSRA is evaluated by GA method and designer can follow a systematic approach to find the most appropriate configuration. Using this approach, the time and the cost of conceptual design can considerably be reduced.