Aircraft behavior can be described by a set of parameters that represent their aerodynamic properties and flight conditions. They are measured in aerodynamic tunnels under some special laboratory conditions. However, they do not fully describe all possible flight situations. Their accuracy is also limited. As considerable changes of the description occur during a flight, the use of non-adaptive autopilots, especially in combat aircraft, is strongly limited. The removal of this obstacle is possible only by means of a continuous on-line adaptation of the aircraft model and by a consecutive adaptation of the autopilot. The paper deals with the design of a performance-adaptive, so-called self-organizing, fuzzy controller as an autopilot. The structure of such a controller as well as the modified adaptation principle with some experiments are described.