Micro air vehicles (MAVs) have grown as an increasingly important field of study in aeronautics research throughout the world for the past few years. The low speed and the small aspect ratio of wings of these airplanes generate a particular flow regime that is still not well understood. The present study uses the commercial software Fluent to consecutively investigate the aerodynamics of airfoils, wings, fuselage, and entire MAVs for angles of attack up to stall. It enlightens the requirements for the proper meshing of the fluid domain and settings of the simulations. Obtained numerical results give an insight on the development of separation as angle of attack increases accounting for the stability of the MAV near the stall. Further investigations give an overview on the propeller, fuselage and wing interactions. Effects of low aspect ratio and planform of wings were studied and were confirmed by wind tunnel testing.