Evolution of U.S. Domestic Airline Route Networks since 1990

Abstract

This paper examines how the networks of both legacy airlines and low-cost carriers evolved and adjusted to the changing competitive and economic environment between 1990 and 2003. The route networks of Air-Tran, America West, American, Continental, Delta, JetBlue, Northwest, Southwest, United, and US Airways are examined. Several measures of operational characteristics are developed and applied to the principal hubs and other dominant airports of each of these carriers. Particular attention is paid to the strategic use of regional jets operated by affiliated carriers and the extent to which passengers used connecting flights as opposed to direct flights. The analysis focuses on how these airlines adapted their use of hubs and route networks during periods of economic growth and recession and how they adapted to other changes in the competitive environment. The legacy airlines have not backed away from the traditional hub-and-spoke network, nor is there evidence of reduced emphasis on connecting traffic. Instead, the dominant change was a dramatic increase in the role of regional jets flown by affiliated carriers in their primary hub airports. The use of regional jets allowed the major airlines to increase the number of aircraft departures and the number of cities served from their hubs between 2000 and 2003 when faced with a reduced number of passengers.