US air passenger service: A taxonomy of route networks, hub locations, and competition

In this paper, we analyze the service provided by the 13 largest US passenger airlines to the 100 most populous US metropolitan areas in 1989. We classify the route systems by their nature and geographic scope using a variety of measures based on route-level data. We then identify individual airline hub locations; derive and calculate several measures of the extent of competition on individual routes, for individual airlines, and at the airports in our sample; and analyze relationships among route structure, costs, and subsequent carrier performance. The results show the wide diversity of route networks that existed in the airline industry in 1989 – a phenomenon that may help to explain the eventual failure of several major carriers.