Airline efficiency and air passenger trip circuity trend

This paper addresses how airline industry consolidation and network realignments affect passenger trip efficiency as measured by trip circuity (ratio of passenger distance flown to direct distance). Over the last 20 years, airlines have dropped many point-to-point markets in favor of flowing passengers through large hub airports. Despite this trend, the portion of passenger origin to destination itineraries satisfied by direct flights has generally been increasing in the US. All else being equal, this trend benefits passengers, air carriers, and the environment, because it means that passengers spend less time traveling; carriers are transporting their passengers more efficiently to their destinations more frequently on direct routes; and there is less fuel required to meet travel demand. However, significant structural changes in the airline industry have coincided with discontinuities in this trend. This paper explores how some of the industry's structural changes have affected this trend, and how this trend is currently being affected.