In this study, a guidance, navigation and control (GN&C) system basedon fuzzy logic control design, namely wingman fuzzy navigation andcontrol system (W-FNCS), is developed for autonomous formation flightand applied to a small unmanned aerial vehicle (UAV) system calledSwallow UAV. It estimates attitude information from single antenna globalpositioning system (GPS) and inertial measurement unit (IMU), stabilizesthe UAV to the desired attitude angle, and navigates the wingman (follower)vehicle to maintain the relative position with regard to the leader onethrough the leader vehicle’s GPS position broadcasted by an inter-UAVnetwork. The W-FNCS is designed by the flight test data, preliminary testedby a hardware-in-the-loop simulation environment (HILSE) and verified bya flight test procedure to ensure safety during the two vehicles’ autonomousformation flight demonstration. The real flight results clearly show that thedesigned W-FNCS has achieved the desired functionality for the wingmanvehicle with autonomous formation flight capability in following the leaderone.