In April 2010, Spirit Airlines announced that they would begin charging travelers for use of the overhead compartments on their planes. Indeed, almost everything on a Spirit flight is priced a la carte. Travelers worried that this approach would spread to other airlines, but at the end of the year, no other carriers were charging for carry-on stowage.

Clearly, however, the traveling public has witnessed an unbundling of air travel costs.

Not all budget travelers are upset by this trend. They point out that many of us pay for services we never use. Why not pay only for the things that matter to us?

If that's going to be the way to price future air travel, it pays to look for ways to avoid as many fees as possible.