System-wide capacity enhancement for the future U.S. airport network: a new generation hub and route optimization model

The welfare of today's air travelers is being compromised with the establishment of airline "fortresses" at many of our nation's major hub airports. The limited capacity of these sites has increased congestion both in the air and on the ground, causing system-wide passenger delays. Proposals to remedy the situation have included computer-based modernization of air traffic control, the building of more airports (and/or the enlargement of existing ones), price controls on slots (i.e., bidding), and government re-regulation. These proposals have focused primarily on the airport as the source of the capacity problem; however, relatively little has been accomplished in the way of a system-wide approach. If direct nonstop service could be offered between every city-pair, then passenger utility would be maximized; and if all destinations could be connected with the shortest possible span, air service utility would be maximized. Obviously neither of these extremes can exist, for the maximum benefit of one represents the greatest cost in utiHty to the other.

Possibilities exist between these extremes, however, that offer "optimized" air passenger service in some sense. In this investigation the computer implementation of a mathematical model was developed to logically explore these possibilities in a spatial way to help planners optimize air passenger service-as it relates to airport capacity enhancement planning. The model was demonstrated on an actual region where measurements of service utility and passenger convenience were determined and compared with other common network types. Results indicated that in terms of network distance, route directness, and number of intermediate stops, branching networks compared favorably with hub-andspoke networks, but with a significant decrease in major hub congestion.