Letters to the Editor
Are Airlines Doing Their Homework?
I recently read an article [2] in The Wall Street Journal that explained how airlines were saving money by loading extra fuel at cities with lower gas prices. The article went on to say that airlines had been practicing "tankering" for years to pinch pennies. I was intrigued to find out that "technology" was currently pushing this trend. Specifically, the article noted that Southwest Airlines recently extended its program to examine multiple legs, as they had previously only looked at the plane's next destination. It also was reported that Frontier Airlines had hired an aeronautical engineer "to design a computer program to calculate potential savings."
Being the eternal problem solver, I pondered the multistage problem. I even discussed it with some of my colleagues. Clearly we were not privy to all of the problem details, but we did not understand why the problem was hard. So I did what any good researcher would do: I went to the literature.
It turns out that Darnell and Loflin [1] reported on a "Fuel Management and Allocation Model" in 1977. The model used a linear program to determine "the best fueling station and vendor for each flight, based on prices, availability, fuel burn, flight data and cost of tankerage." The work was motivated by the oil crisis, which resulted in fuel rationing for airlines. Despite the (slightly) different context, the solutions seem strikingly similar to those desired today.
I know I should not jump to conclusions. The article only summarized the approaches and clearly did not spell out the details. Furthermore, there may be some issues relevant today, such as oil price hedging, that were not considered in the original work. But for as much we read about the airlines using O.R. in practice, I cannot help but think that someone out there is not doing his or her homework (see Problem 57 of Chapter 3 on Page 123 in Winston [3]).
Joseph C. Hartman
Bethlehem, Pa.
Joseph C. Hartman is an associate professor and interim department chair, Industrial and Systems Engineering, Lehigh University.
References
- Darnell, D.W. and C. Loflin, 1977, "National Airlines fuel management and allocation model," Interfaces, Vol. 7, No. 2, pp. 1-16.
- Trottman, M., 2004, "Fill 'Er Up: Airlines Hop Around Cities for Cheaper Fuel," The Wall Street Journal, B1, Nov. 12, 2004.
- Winston, W.L., 2004, "Operations Research: Applications and Algorithms," Fourth Edition, Thomson Learning, Inc., Belmont, Calif.
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