It happens all the time: you buy a plane ticket and then the next day, the next week, or the next month, you discover that you can now buy it on the same flights, same days of travel, same fare class (or "fare bucket" in airline-speak) on the same website for less money.

For instance, you booked Anchorage from Los Angeles on Alaska Airlines ( You did it on (just the way the airline likes it). Now, the same fare is being advertised for much, much lower. Bet you wish you could get some of that money back.

The good news is that you can. Alaska, along with a handful of other airlines, does reward those who do their homework after booking. OK, so it's not exactly money back, but it is a credit of some sort (electronic if you're lucky; an annoying paper voucher if you're not), good for future travel for up to a year.

Sounds nice, right? Don't get too comfortable Â? Alaska is in an elite group of airlines that makes it easy for you. Southwest ( is another one (AirTran -- now a part of the Southwest family -- recently adopted its parent's policy as well). While Alaska and other airlines don't have a printed policy, they do allow customers to rebook without incurring fees; any credit is issued to the customer's account. Savvy JetBlue ( customers that find lower fares after booking know to give reservations a ring; if it all checks out, the airline will credit the difference to use for future flights, stored in your account for use within a year (again, this is not a published policy, just so you know.)

It goes downhill -- fast -- from here. Many airlines, most notably non-U.S. carriers and no-frills airlines such as Spirit (, won't give you anything back at all. And if they do, most charge a change fee of up to $150 on a domestic fare and $250 or more on an international one. In other words, that had better be one doozy of a fare drop. But all bets are off if you bought your fare on ( or another so-called "opaque" site, or if the fare is bought from a consolidator.

Check out our chart showing how various U.S.- and foreign-based airlines compare. You'll see that especially if you're traveling internationally and you're a fare-watcher, then you're better off sticking with U.S. carriers rather than foreign ones.

But before you get too mad at the airlines for not giving the entire fare difference back to you, consider this: how many merchants do this? I recently got an e-mail about a semi-annual sale at Brooks Brothers specifically stating that prior purchases were not eligible. If you buy a TV at Best Buy and discover five months later that the price has gone down, do you honestly think that they'll refund the difference (maybe there's a seven-day or perhaps a 30-day price guarantee, but some airlines will issue refunds on fares bought months ago). And frankly, with all the new ways airlines are devising for raising revenue, it wouldn't surprise us one bit if they start acting more like other retailers. As in: You buy it, you fly it.

George Hobica is a syndicated travel journalist and blogger whose website,, tracks unadvertised airfare wars and fare sales, including the most helpful and always updated Top 50 Airfares.

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