Thanksgiving is almost upon us, which means we’re in the middle of the busiest—and, if you include the holiday itself, least busy—travel days of the year. Nearly 25 million people are projected to fly on U.S. airlines during the 12-day period between Nov. 21 and Dec. 2.

Some of these passengers booked their flights months in advance, snagging the lowest fares; those who purchased tickets in the past few weeks typically paid much, much more; a rare few lucked out with last-minute deals. Three people sitting side-by-side in the same coach cabin seats most likely paid dramatically different fares.

It is not surprising that, with such a large number of people wanting to travel on very specific days, the airlines charge a premium for these limited seats. But one of passengers’ biggest frustrations with air travel is the complex, cryptic, and seemingly unfair pricing systems, which create a high variability in what different customers pay for the same service. Why can’t the airlines just charge one single, simple fare for each flight and treat everyone on that flight the same? Wouldn’t we all be better off?

Probably not.

The airlines, being for-profit companies, set prices to maximize revenue. But at least to some degree, their pricing systems can work to passengers’ advantage as well—even to those who end up paying the highest fares.