Domestic Airline Mergers and Defining the Relevant Market: From Cities to Airports

In 2017, more than four billion people in the world used aviation to travel. Airlines within the United States transported 741 million passengers domestically. As passenger demand for air travel has risen astronomically, the number of airlines who serve domestic passengers has dwindled to five major U.S. airlines. This shift in the airline industry and the reduced number of domestic airlines requires the Department of Justice (DOJ) Antitrust Division (Antitrust Division) to alter its analysis of airline mergers to determine their anticompetitive ramifications. This article serves as guidance for the future of airline mergers within the United States. It argues city-pairs should not provide the only method of defining the relevant market and that airports should be included in the relevant market determination. To accomplish this, Part II will provide the background of antitrust law and the airline industry by describing the historical development of the governing legal rules and the Antitrust Division’s oversight of merger law. Part III will discuss the development of defining the relevant market in airline mergers by analyzing the evolving approach the agency has taken to airline mergers over the past twenty-five years. Part IV will critique the current ways of defining the relevant market within airline mergers, and Part V will provide suggestions for determining the relevant market and alternative ways to assess entry barriers