This paper presents the design of Unmanned Aerial Vehicles (UAVs) formation flight control laws and then the virtual Environment setup of a nice structure for close formation flight. The images of the target airplane projected on the video-camera plane of the follower airplane are captured and processed into vision information The simulation setup includes airplane dynamics, autopilots and formation keeping controller and module that creates virtual environment for the simulation of the vision software called Unity3D. The UKF is applied to the relative motion estimator due to the highly nonlinear characteristics of the problem.