The research is focused on development of Unmanned Aircraft System. For design purposes Systems Engineering Approach is used. This paper describes concise research for Unmanned Aircraft System air vehicle preliminary developments phase. The design is focused on development of micro Unmanned Aircraft System with long range and endurance capabilities. In current paper UAS air vehicle wing airfoil selection process is described. In previous design steps the air vehicle type for Unmanned Aircraft system was selected that is flying wing configuration. The flying wing air vehicles have inherent stability and controllability problems that should be eliminated selecting right airfoil shape. In wing airfoil selection Multidisciplinary Optimization Method is used to get airfoil that will give necessary results to reach design goals. Most frequently used Multidisciplinary Optimization Method are Finite Difference, Implicit Function Theorem, Stepping Search Methods, Response Surface, Monte Carlo, Random Walk and Simulated Annealing, Evolutionary Algorithms and Evolution Strategy, Genetic Algorithms, Decomposition. In current research for airfoil selection Stepping Search Method was used. Obtained results provided clear and uncompromising information for further design steps and complete wing design.