Integrating multiple features for autonomous flight of aircraft requires extensive research over wide categories, high-level of know-how, and experiences. To contribute to these issues, this paper treats the realizable integration techniques of the path planning, trajectory generation, and trajectory-tracking control for the mission autonomy of the aircraft. A collision-free path over the three-dimensional digital terrain is efficiently generated using the P-RRT* algorithm and optimized using the line-of-sight path optimizer proposed in this paper. After additional waypoints are inserted into the planned straight-line path segments, a flyable trajectory for the position and heading angle can be built using the spline trajectory generator with reference to the prescribed velocity distribution. Finally, the incremental backstepping-control design has been adopted to provide accurate trajectory-tracking control. The paper addresses in detail the underlying rationales of the present selection of each technique from the realizability point of view. The integrated designs are validated through simulation studies for a series of autonomous mission scenarios of the rotorcraft. The results show that the P-RRT* algorithm combined with the line-of-sight path optimizer can provide a fast and efficient solution for path planning. Also, the extremely accurate trajectory-tracking performance has been achieved by applying the incremental backstepping control to the flyable trajectory obtained using the spline trajectory generator.