Multirotors are one of the most popular types of small unmanned aircraft systems today with applications in many areas including but not limited to aerial photography, transport, military, surveillance, agriculture, and leisure. Autonomous flight controls is one of the key enabler technologies for their popularity and growing applications. Many studies about the flight controls for multirotors have enhanced the control performance, but we still have rooms to improve in tracking accuracy and efficiency. This paper presents an autonomous flight control method for multirotors based on a simple input-output linearization coupled with nested saturation. We choose an unconventional, alternative output of the multirotor flight control system, which leads to reducing computational cost regarding Lie algebra when we linearize the system dynamics. Then we stabilize the linearized system with nested saturation with real poles of our own choice. Given the desired output through the outer loop PID controller, the results of the simulations show that the error dynamics regarding the outputs are stabilized exponentially fast.