Even though Kurt Johnson doesn’t work for the TSA, that doesn’t stop him from lending a hand when he’s stuck in a long line at a security screening area. “I’ll sometimes grab an extra tray or two to help move things along,” says Johnson, who runs a fitness Web site in Los Angeles.

Like most frequent air travelers, Johnson has always suspected that the main cause of travel delays aren’t the operational challenges that airlines, buses and trains face, but other people. New research may prove him correct.

Prof Vikrant Vaze

A study now in progress follows up on the findings of scientists at Dartmouth College, MIT and the University of Texas at Austin, which concluded that although the average flight delay is 15 minutes, this translates into an average half-hour holdup for passengers because of missed connections and cancellations.

That made Dartmouth engineering professor Vikrant Vaze wonder about the root causes of delays. Specifically, who’s to blame for most of them: airline crewmembers or passengers? “There are various ways delays can happen,” he explains. “Right now, the effect of aircraft disruptions is fairly well researched. The impact of crew and passenger unavailability is less well studied.”

Passengers already have their own theories, and they aren’t shy about sharing them. Their anecdotes offer a few strategies for lessening travel delays, at least until Vaze’s research is done...

...Coming up with a solution to passenger-caused delays may be the provenance of researchers like Vaze, the Dartmouth professor. He wonders not only about the blame-breakdown between airline employees and passengers, but also about how the study might affect airline policy. “Perhaps we’ll know that crew contributes X percent of the delays,” he says. “But will it be 1 percent, or 5 percent, or 20 percent? We don’t know yet.”