This paper proposes an automatic flight control law design methodology for a trajectory tracking problem by use of hierarchy-structured dynamic inversion approach, which is based on multi-time-scale separation and multi-loop closure method. It considerably simplifies a flight control design compared with the conventional PID approach which is augmented with the gain scheduling technique. It realizes a universal design of the controller which utilizes the vehicle's 6DOF simulation data on board. The dynamic equations employed are categorized into four groups according to their time-scales in a physically natural manner, where the variables in each category are controlled by the faster variables in the adjoining category. In this paper, preliminary evaluation using a linear model is carried out in the first place to ensure the validity of the approach, and a further analysis is conducted with a 6DOF simulation model.