PURPOSE: To make a plan in real time by effectively using characteristics of a helicopter and enabling it to reach the target of its duty without being recognized as a threat and avoiding the internal strife due to erroneous shooting of friends.

CONSTITUTION: Data indicating the target, the arrival time, the base, etc., is inputted from an input device 6, and data of flight corridors, weather, threat, etc., of a communication equipment 2 obtained from an external system 8 is discriminated by an online controller 4 and is stored by a dynamic data base 3, and the flight plan including an optimum route and a flight summary obtained by processing of data of the data base 3; and the input device 6 and required time and fuel calculated in accordance with the optimum route and the flight summary is displayed on a display device 7, thus making the optimum flight plan effectively using the characteristics or the helicopter in real time.