Flying Fears Revealed: Effect of September 11, 2001 Terrorist Attacks on Short-Term Domestic Airline Ridership

Student Author(s)

Ethan J. Beswick

Faculty Mentor(s)

Dr. Sarah M. Estelle

Document Type


Event Date



Over the course of the last 15 years, the United States has never recorded a lower month of enplaned passengers on domestic flights than September, 2001. This particular month was marked by the terrorist attacks of September 11, 2001, and the total airline ridership count dropped by 26 million passengers—a 47 percent drop—from the previous month (Bureau of Transportation Statistics). With significant media attention on the attacks, the potential dangers of flying were once again revealed, resulting in passengers choosing not to fly as frequently, if at all. This study attempts to quantitatively explain what effect this fear had on ridership immediately following the 9/11 attacks. Using Department of Transportation data, airline ridership is examined in order to determine what percentage of the resulting decrease in ridership can be attributed to passengers’ fears of flying and what role mediating factors could have in the decreased number of passengers choosing to fly. Using a difference-in-differences model, the top 30 airports, as measured in terms of enplaned passengers, are compared to smaller airports before and after the 9/11 attacks. The resulting regression shows a significant drop in ridership at the largest airports which is consistent with an additional fear of flying from these more heavily trafficked locations.

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