A formal approach for the mission planning and control of unmanned aircraft is described. Linear hybrid automata are used to model the chosen aircraft, the resources needed to perform a mission and the environment in which the aircraft will operate. This mission model can be verified with respect to safety criteria, like not running ou of fuel, or used to perform parametric analysis, allowing the instantiation of symbolic parameters in flight plans for specific missions. Later, during mission execution, an on-board flight controller is used to control the progress of the mission by reacting to relevant external and internal events.