Frequent flier programs: Want to know what the best frequent flier program is? Here's a hint: There isn't one. In speaking with Tim Winship, travel industry website SmarterTravel's expert on frequent fliers, the lines between the carriers' rewards plans fade from gray to nearly nonexistent. For example, AirTran ( AAI) customers may miss the carrier's business-class seating once it merges with Southwest Airlines ( LUV), but they'll miss its A+ Rewards frequent flier program less than they think. Why?

"The big picture, as far as I'm concerned, is that the decrease in competition erodes the incentive for airlines to be more innovative with their frequent flier programs," Winship says. "The AirTran program and the Rapid Rewards plans are quite similar because, as a historical matter, AirTran copied Southwest's rewards program, as many of the discount airlines did."

United ( UAL) and Continental's programs have been so closely aligned that there isn't much separation between the programs. Delta ( DAL) consolidated Northwest's program into its SkyMiles program. They all offer more opportunities to earn miles than can be listed here and, in their rewards sheets, the amounts of miles needed for redemption aren't significantly different from one another. The key separations are destinations and available reward seating, with the first being easily more measurable than the last. Winship says that when SmarterTravel asked him for a "Best Frequent Flier Program" for their annual editors' choice awards, he replied simply that there wasn't one -- that there are big-carrier rewards programs and small-carrier rewards programs, and that JetBlue's ( JBLU) recent tweak of its frequent flier program showed just how quickly they're homogenizing.

"They redesigned and relaunched their program along the lines of the Virgin America program, which is revenue-based where you earn points according to the cost of the ticket purchase, and that's the model I expect Southwest to go with when they revamp Rapid Rewards."

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