Flight control for a quadrotor is a complicated task because of the complexity of the flight trajectory program and the uncertain changes in aerodynamic parameters, which make the system more complicated and nonlinear. Flight path angle tracking control consists of varied channels, such as a pitch controller, a roll controller, and a yaw controller. They are usually designed using traditional linear control methods, but this is not always satisfying, hence the more effective approach to controller design is backstepping. The backstepping control laws not only give the controllers certain gain margins but also deal with model errors in the description of aerodynamics. This paper presents a backstepping nonlinear controller design method for control systems involving quadrotors. Simulation results show that the control strategy proposed in this paper is effective and has strong robustness in the presence of disturbances and parameter uncertainty.