The increasing potential applications of Unmanned Aerial Vehicles (UAV) provides the motivations for numerous research to focus on developing fully autonomous and self guided UAVs with the purpose of controlling UAVs in confined environments. Current UAVs control systems are not able to offer the precise trajectory regulation required in autonomous flight technology. These systems fail to control aerial vehicles’ performing complex maneuvers through confined environments because current UAV designs do not have suitable control mechanisms providing agility and stability for the required maneuvers. New advances in control theory are required to overcome these limitations in order to enable aggressive autonomous vehicle maneuvering while adapting in real time to changes in the operational environment. This thesis addresses a control problem of an unconventional highly maneuverable Vertical Takeoff and Landing (VTOL) UAV, using tilted ducted fans as flight control mechanism. The main purpose of this research is to design a nonlinear control methodology that enables the vehicle to use the full potential of its flying characteristics for independent control of its six degree-of-freedom, including orientation and position of the UAV. This thesis investigates maneuvering inside obstructed environments in the presence of external disturbances such as wind, ground and wall effects. Achieving this goal is possible due to a revolution in aviation control by introducing Oblique Active Tilting (OAT) mechanism. Capabilities of OAT system will be fully used in controlling the UAV to enhance its maneuverability.