The system developed is intended as a tool for use by the decision maker. That decision conceivably could be made by a city planner, a planning group, an airport manager, a county board of commissioners or the head of the Civil Aeronautics Board. At any rate, the decision maker is the man or group to decide whether existing passenger air service for the defined area is adequate or inadequate. In so doing, he must ascertain the supply of that existing air service. This decision maker then, through the exercising of his supply-tool and his demand-tool, scientifically arrives at the decision.