The North American Airline Industry

Is it an Oligopoly?

The United States airline industry today is arguably an oligopoly. An oligopoly exists when a market is controlled by a small group of firms, often because the barriers to entry are significant enough to discourage potential competitors. While the airline industry in the U.S. is largely represented by a handful of companies, there's still room for new airlines to gain a foothold.

Key Takeaways

  • One could argue that the U.S. airline industry is an oligopoly, controlled by the four main domestic carriers: American Airlines, Delta Airlines, Southwest Airlines, and United Airlines.
  • The Airline Deregulation Act of 1978 removed the Civil Aeronautics Board's (CAB) power to regulate the U.S. airline industry.
  • Without federal government control, airlines were free to set routes, increase the number of flights, and adjust fares.
  • Over time, the airline industry experienced consolidation, with a number of carriers merging to form the top carriers that dominate market share.
  • With fewer carriers, competition has decreased and some government officials claim airlines are holding back on expanding capacity in order to keep fares higher.

The Major Airline Players

As of 2021 there are four major domestic airlines—American Airlines, Inc. (AAL), Delta Air Lines, Inc. (DAL), Southwest Airlines (LUV), and United Airlines Holdings, Inc. (UAL)—which fly just under 70% of all domestic passengers.

As of 2021, American Airlines had the largest market share with 19.6%. Southwest is close behind with 18.1%, while Delta and United have 14.7% and 11.5% respectively. Air travel saw a marked decline in 2020 due to the global crisis and lockdown. Rather than reporting a profit, the airline industry reported a net loss of $126.4 billion, though recovery is expected in 2021 and beyond.


Avelo Airlines and Breeze Airways joined the U.S. domestic airline landscape in the spring of 2021, offering flights on the West Coast and the southeast and central U.S., respectively.

Changes in Regulation

Between 1937 and 1978, the Civil Aeronautics Board (CAB) managed domestic air travel in the U.S. like a public utility. The group was responsible for establishing schedules, fares, and routes. Airlines that saw demand for new routes were forced to apply for CAB approval, which often was not forthcoming. Consequently, they were frequently forced to seek judicial intervention in order to get routes approved.

The Airline Deregulation Act was introduced in 1978. Its effect was to increase competition, with fare prices decreasing in the 20 years following its introduction. Meanwhile, the number of fares increased from 207.5 million in 1974 to 721.1 million in 2010.

However, after extensive consolidation in the industry (high-profile mergers such as Delta with Northwest in 2008, United Airlines and Continental Airlines in 2010, Southwest and AirTran in 2011, and American Airlines and US Airways in 2013) and the failure of many smaller airlines, prices began to rise sharply, continuing to climb in early 2016, despite the sharp fall in the cost of fuel.

In recent years, the four major airlines have removed unprofitable flights, filled a higher percentage of seats on planes, and slowed capacity growth to command higher airfare. Capacity has, as a result, grown at a far slower pace than ticket sales. In addition, since 2008, the airlines have charged ancillary fees for services that were earlier included in the airfare.


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Becoming a Cartel?

Lawmakers and passengers have been crying foul over the airline industry's move toward oligopoly status. “Consumers are paying sky-high fares and are trapped in an uncompetitive market with a history of collusive behavior," Connecticut Sen. Richard Blumenthal, Democrat, stated in a letter to Assistant Attorney General William Barr on June 17, 2015.

The entry of low-fare foreign competition such as Norwegian Air International and the expansion of smaller domestic players have been actively discouraged by the top airlines. With fewer companies, tacit collusion is likely and competition is minimized. Fares are kept higher and the frequency of service relatively lower without any explicit agreement among the market participants.

With the relationship between competing airlines appearing too cozy for comfort, in July 2015, the Department of Justice (DOJ) launched an investigation into the airline industry. The carriers were asked to submit copies of all communications to airline executives, shareholders, and investment analysts about capacity plans. The investigation followed public statements by airline executives at an IATA gathering, which highlighted the need for “capacity discipline.”

According to David McLaughlin and Mary Schlangenstein for Bloomberg Business, the DOJ is looking at whether airlines have been communicating strategy with each other through their major common shareholders, including BlackRock Inc., State Street Corporation, JPMorgan Chase & Co., Primecap, and Capital Group Companies. Academic studies indicate common investor ownership of competitors may be challenged as anticompetitive even if overt coordination is not involved. This situation presents a conflict between the interests of the common investors of the airline companies seeking profit maximization and those of the customers seeking lower fares and route options.

Airline executives may hold back from expanding capacity or lowering prices, as it is against the interests of their biggest shareholders, who also own stakes in their competitors. Executives could even coordinate strategy on pricing or capacity through discussions with large common investors.


While the pandemic caused disruption to airline industry revenues, there was an upside for travelers--a significant drop in the average domestic fare from $352 to $291.

The Bottom Line

The DOJ’s ability to bring criminal charges against the airlines depends on whether any documentary evidence of collusion exists. This seems unlikely in light of the industry’s experience with past antitrust investigations. Still, the investigations are costly for the industry. Even if airlines avoid having to pay billions in fines, they face spending millions of dollars in legal fees.

Article Sources

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  1. Bureau of Transportation Statistics, U.S. Department of Transportation. "Airline Domestic Market Share." Accessed May 24, 2021.

  2. IATA. "Reduced Losses But Continued Pain in 2021." Accessed May 24, 2021.

  3. AP News. "Startup Breeze Airways says it will begin flying in late May." Accessed May 24, 2021.

  4. Federal Aviation Administration (FAA). "A Brief History of the FAA." Accessed May 24, 2021.

  5. United States Government Accountability Office. "Airline Deregulation: Changes in Airfares, Service, and Safety at Small, Medium-Sized, and Large Communities." Accessed May 24, 2021.

  6. Bloomberg. "Airline Deregulation, Revisited." Accessed May 24, 2021.

  7. Airlines for America. "U.S. Airline Mergers and Acquisitions." Accessed May 24, 2021.

  8. United States Government Accountability Office. "Commercial Aviation: Information on Airline Fees for Optional Services." Accessed May 24, 2021.

  9. Richard Blumenthal, United States Senator for Connecticut. "Citing Unprecedented Consolidation within Airline Industry, Blumenthal Urges DOJ to Investigate Potential Anti-Competitive, Anti-Consumer Behavior and Misuse of Market Power." Accessed May 24, 2021.

  10. New York Times. "'Discipline' for Airlines, Pain for Fliers." Accessed May 24, 2021.

  11. Journal of Finance. "Anticompetitive Effects of Common Ownership." Accessed May 24, 2021.

  12. Bloomberg Business. "U.S. Airlines Face Antitrust Probe Into Possible Price Collusion." Accessed May 24, 2021.