Air transportation carriers can find some feasible solutions for energy-saving with appropriate performance. The wing in ground effect (WIG) aircraft possesses higher lift-drag ratio, higher payload and rapid transport under less energy consumption for short-medium transportation. A preliminary design on WIG aircraft in high aspect ratio for lower speed and higher payload based on unmanned aerial vehicle (UAV) is studied in this paper, including aircraft structure and aerodynamics analysis. Considering system performance, when WIG aircraft flies in ground effect, its longitudinal stability is weaker than in the air. Airfoils should be modified for a suitable design to smooth its sensitive longitudinal motion. For prompt system validation, the prototype design is built using SolidWorks, and its fluid field analysis is simulated using ANSYS/Fluent and XFLR to examine its aerodynamic effect around the wings. The simulation on this aircraft verifies the performance of ground effect. Several critical criteria in WIG design are settled in lift-drag ratio, coefficient of moment and longitudinal stability. An unmanned WIG aircraft is fabricated and implemented in remote control into flight tests. The prototype UAV model of WIG carries a series of flight tests to compare with the numerical simulation results. The proposed system design and test verifies that the high aspect ratio wing make positive contribution to WIG aircraft in the ground effect zone.