In this paper, we study the trajectory tracking problem of autonomous small airplanes in presence of unknown wind gusts. The vehicle is represented by its center of gravity, and the mathematical translational model is derived using Newton's second law. The controller is designed using Robust Control Lyapunov Function and Sontag's feedback stabilizing universal. The proposed control laws guarantees, by structure, the robustness of the system with respect to different uncertainties due to model and unknown external parameters. Numerical simulations are performed to demonstrate the performance of proposed control strategy.