You don't hear much about budget airline Allegiant Air, even in the U.S. as the airline has quietly carved out its own unique business model based on fees and vacation packages. But an idea to charge fares with a final price tied to the cost of fuel on the day of travel is surely getting attention. Will we be seeing adjustable rate fares in the future?

Allegiant Air and just about every other airline are looking to stave off rising costs, mostly from spiking fuel prices. Ancillary fees and fuel surcharges have been the most common approaches to alleviating such financial stress. Allegiant is no stranger to fees and bases its model on offering very low fares; flying to underserved and vacation destinations; and adding a healthy amount of fees. Now the airline is thinking about having customers hedge their bets on the final cost of an airline ticket based on the price of fuel.

The idea is based on the fuel hedging that many airlines currently participate in. Basically, they guess at the future price of fuel and pay to "guarantee" this price for a set period of time. If the price goes up, they get their fuel for the cheaper price. If the price plummets, the airlines wind up having paid more. It's a gamble airlines take in exchange for the predictability in fuel costs – and the hope that prices will be cheaper in the long run. Are Allegiant's customers willing to make such wagers?

Allegiant says that it would like to be able to offer customers a choice of a fixed-price fare as they do today (though fees are inevitably added on), and a variable-price fare which would be initially cheaper. The cheaper fare would eventually be tied to the price of fuel on the departure date. If the price of fuel is higher, the customer would have to cough up more cash on the departure date. If the price of fuel drops, a refund is given for the difference. It seems that this tactic might snare a few interested travelers looking for rock-bottom prices with a little playful risk involved. Government authorities on the other hand may not be so amused.

The U.S. Department of Transportation (DOT) is proposing new rules that would require greater pricing transparency. The total cost of an airline ticket – taxes, fees and all – must be known to the customer early in the booking process. In addition, the rules would also prohibit a price increase once the ticket purchase is made. The rules are undergoing a public comment period and among those expressing opposition to the fare increase prohibition is Allegiant Air. Their new idea was meant as an alternative and the airline says that it wants the flexibility to offer it in the future.

Right now, the idea of a flexible fare based on the final cost of fuel is just a concept. Customers willing to bet that their ticket will be cheaper in the end might like it and could find the gamble worth it. Did we mention that Allegiant is based near Las Vegas?