Nowadays one of the main lines of development in aerial craft is the design and construction of unmanned aerial vehicles (UAV’s). Within this wide topic, development of ultralight (UL) aircrafts is especially popular because of their versatility and relative low cost. My task was to design the shape of an airplane wing-fuselage junction, which will be classified as an ultralight and unmanned aerial vehicle. The most optimal wing-fuselage junction is made with the Ansys simulating program, including model calculations. Based on the calculations and results, solutions can be recommended. With CAD geometry models, first stage of testing of the aircraft with 3D printed models, is prepared.