Airline checked-bag fees might not ever become popular with travelers. But the fees have reduced departure delays, according to a study published in the August edition of the peer-reviewed journal Management Science.
In reaching that conclusion, the study's four authors, one each from the University of North Carolina, the University of South Carolina, Kansas University and Eastern Michigan University, analyzed data from more than 9 million flights that launched between May 2007 and May 2009, in which most major U.S. airlines implemented baggage fees.
In so doing, the authors compared delays at airlines before they implemented the fees with delays afterward. They also compared the results for airlines that have fees, with the notable exception of Southwest. The study, called "Do Bags Fly Free? An Empirical Analysis of the Operational Implications of Airline Baggage Fees," controlled for outside factors such as weather delays, the age of aircraft and the number of passengers on a flight in an attempt to isolate the operational impact of baggage fees.
An assumption made by many travelers, the authors noted, is that because baggage fees have led to passengers carrying more bags onto the plane -- thereby complicating the boarding process -- they have increased delays.
But what passengers don't see is what the authors call the "below the cabin" effect, in which the baggage fees have reduced the number of checked bags, making the process of loading and screening such bags more efficient.
In running their data comparison, the authors found that when most airlines implemented a fee for a second checked bag it resulted in a reduction in the average departure delay of 1.3 minutes. When carriers subsequently began charging for the first check bags, departure delays dropped two minutes.
"Our study provides an empirical support that the checked baggage fee policies were associated with an improvement in a key airline performance metric, on-time departure performance," the authors wrote.
The study also showed that even though it still doesn't charge for bags, Southwest saw shorter delays after other airlines implemented the fees.
"One possible explanation for this carryover effect is that, at many airports, the security screening and processing of checked bags is centralized, so that fewer checked bags by any of the airlines benefits all of the airlines which fly from that airport," the study said.
However, the change in delays for Southwest was less pronounced than for other carriers.