Give frequent fliers more reward options

And once carriers realized their frequent-flier programs could be sales incentives much as Green Stamps once were, they've been selling miles to merchants who offer them as bonuses on purchases, often at multiples of four or five miles for every dollar spent. In addition to earning free flights by buying plane tickets, program members can amass mileage credits booking hotels and renting cars with participating providers or just using affiliated credit cards to make normal purchases.

Millions of travelers have traded in these credits for free seats, which are carefully doled out by carriers. Award mileage can also generally be used for upgrades to business or first class or to get free seats on affiliated carriers.

Amazingly, despite the traveling public's general frustration with airlines these days and the perceived difficulty of getting free seats they want on a diminishing number of flights, the programs continue to be popular incentives, with many people racking up mileage credits faster than they can be used.

According to the publication Inside Flyer (www.insideflyer.com) which tracks travel incentive programs, over 70 percent of airline mileage credits now accrue from activities other than flying, and more than 17 trillion miles have been earned but remain unredeemed.

While the value of a free seat arguably along with ticket prices, most carriers are now tacking on a variety of charges, from fees for booking, security and airport usage to baggage assessments and fuel surcharges. Awards that were once free can now cost $100 or more.

This huge and growing backlog in award mileage represents an enormous liability for air carriers, one which they must show on their balance sheets. In addition to raising the mileage requirements for free seats, some, such as US Airways, have instituted rule changes that have credits expiring if there is no activity in an account within a given period, which can be as little as 18 months.

Recently several carriers have experimented with another tactic, to provide program members with additional reward redemption options.

This represents something of a revolutionary approach because previously no airline program allowed the use of mileage credits for anything other than free seats or upgrades.

While one could earn frequent-flier miles by booking a hotel room or renting a car, but you couldn't use those miles to get a room or a car, a feature that has long been common with hotel affinity programs and some credit card reward programs, like American Express.

American Airlines has instituted its "redeem AAmiles" program, which lets its AAAdvantage members exchange their mileage for free nights at Hilton and Marriott hotels or for free rental cars at Avis, Alamo, Budget or National.

United Airlines now gives its Mileage Plus members the option of trading 1,000 miles for $25 coupons which can be used at more than 8,500 restaurants that participate in the restaurant.com program.

Continental One Pass members can use their miles to bid on merchandise and event tickets at online auctions conducted on its Web site. And Alaska Airlines, whose Mileage Plan has just been named the top airline program of the year for the fourth time by Inside Flyer, maintains an active list of redemption opportunities other than travel.

More carriers should develop similar programs to let their frequent fliers trade their earned credits for goods and services other than free seats or upgrades on their planes, especially since flying itself seems to be increasingly problematic.

Although frequent flyer programs were initially conceived as a way to fill otherwise empty airline seats, their premise changed when carriers began peddling their award miles to be used as sales incentives by other companies.

If they're going to trumpet their programs and promote the accumulation of mileage by all means possible, it seems only fair for hosts and participant companies to provide passengers with ways to use their miles other than by getting on a plane.