This paper proposes a fuzzy interval type 2 logic based autonomous lateral flight controller for UAVs (unmanned aerial vehicles). The implementation framework utilizes MAT-LAB's standard configuration and the Aerosim Aeronautical Simulation Block Set which provides a complete set of tools for rapid development of detailed 6 degree-of-freedom nonlinear generic manned/unmanned aerial vehicle models. The Aerosonde UAV model is used in the simulations in order to demonstrate the performance and the potential of the controllers. Developed controller is also compared by a traditional PI controller. The simulated test flights indicate the capability of the approach in achieving the desired performance.