Herein, the integrated design process of guidance and control systems required for the design of autonomous flight systems for aircraft is discussed. The system can generate a trajectory using real-time path planning, re-plan the path, and accurately track the created trajectory. The real-time path planning is implemented using a rapidly-exploring random tree-based algorithm. Furthermore, the problems with the real-time rapidly-exploring random tree-based algorithm and possible solutions are discussed accordingly. The control system is implemented by incremental backstepping control, which ensures trajectory tracking performance across the entire flight envelope. To verify the series of processes, simulations are run using the high-fidelity Bo-105 model. The effectiveness of the real-time PQ-RRT* and path optimization algorithm proposed in this work is verified by the simulation results.