This paper presents a hierarchical flight management and control system for UAVs. The system composed of three layers, i.e. command interpreter layer, path planner layer, and auto-pilot layer. Path planner layer which plans a UAV's path before flight and during flight is focussed in this paper, and it is done in two steps. Macroscopic path planning is done using evolutionary computation, and microscopic planning is done applying total energy concetp especially in terminal phase and emergency landing. In the former, waypoints are directly determined by evolutionary computaion featuring unified way of handling static and dynamic obstacles, and insertion and deletion of the waypoins. In the latter, microscopic path is determined based on total energy concept which is the sum of the potential and kinetic energy, and remaining fuel as energy. Some example off-line calclation results applying these concepts are also presented.