| Abstract: | This paper surveys changes in the U.S. National Airway System since the 1960s. The most appropriate measures for summarizing air traffic distributions at airports are investigated, with the Gini Index of Concentration being used extensively to analyze U.S. airport traffic patterns over a twenty-four-year period. The properties of the Gini index and other measures are compared and discussed in detail in the context of analyzing air traffic distributions. It is shown how concentration in the traffic patterns at the larger airports was at a high level prior to deregulation, but since 1978, the patterns have gradually become even more concentrated. |
