The Role of Market Structure in Airline Mergers: Evaluating Alternative Causes of Delays

We consider the role of market structure in determining airline delays by analysing the effect of market concentration and market share on delays. Models based on these variables give signifcantly different predictions for how mergers af fect delays. To determine which model is best, we provide misspecifcation tests. Using US domestic airline delays between 2004 and 2019, we find that market share–based models are misspecifed, whereas market concentration models are not. Under the market concentration–based models, mergers cause airline delays to increase, with a larger share of the delays occurring on flights offered by the airlines not involved in the mergers.