The history of flight control cannot be considered separately to the history of aviation. Since the early days, the conception of automatic flight control systems has advanced from mechanical control systems to greatly developed automatic fly-by-wire flight control systems which can be found in military jets and civil airliners these days. Even today, several research attempts are made for the further advancement of these flight control systems in numerous aspects. Current advancements in this area target a variety of different aspects. This book presents a collection of knowledge on important research areas, like inertial navigation, handling of unmanned airplanes and helicopters, trajectory control of an unmanned space re-entry automobile, aeroservoelastic control, modifying flight control, and error tolerant flight control. It discusses theoretical outlook and current conceptual advancements in flight control systems along with describing theories of modified and fault-tolerant flight control systems. Each technique has been elaborated using illustrations and appropriate examples.