How to cash in your miles for a free seat

It's pointless to let your frequent flier miles sit around gathering dust. If you can't redeem them for a free ticket, an upgrade, or even a magazine subscription, they're essentially worthless. They don't earn interest in your account, unlike real currency. And over time, their effective value is bound to decrease, as airlines will inevitably raise the cost of their awards.

Plus, the competition for the most highly-desired seats is only going to heat up. There are thousands of opportunities to earn miles, and millions of people going after them. Many airlines are cutting their flight schedules, limiting opportunities for free tickets. And with so many carriers in financial trouble, the likelihood your miles will still be around when you're ready to use them is less than it once was. So the time to use your miles is now. But how can you maximize the chances you'll find an available award seat?

Similar to searching for a sale fare, the keys to snagging a frequent flier award are flexibility and persistence. For a popular destination in peak season, like Europe in the summer, it's best to start inquiring about award seats 330 days, or approximately 11 months, before you'd like to travel. That's when airlines begin loading flights in their reservations systems. Sometimes that won't happen exactly on schedule, so it's a good idea to call the airline a few days before to try and book your flight.

It's much easier to score a free seat if you can be flexible with your travel plans. Some airlines offer online tools that search a range of dates for award seats. If there are no awards on your preferred travel day, American will display flight combinations on the next available date. For a given month, US Airways will show you dates when you can get an award ticket. And Continental tries to be helpful by providing a color-coded calendar that shows when seats are open. However, its calendar doesn't illustrate which days have availability at its "standard" (25,000 mile) levels, so you need to check each date individually if you don't want to spend more miles than you need to.

If you're having trouble finding seats at all, consider changing your routing. Can you fly from your home city through a different hub airport to your destination? Can you travel to or from a nearby airport instead? Or can you make a stopover on an international trip that opens up award seats on a different day?

You could also consider an award on a partner airline. For example, try using US Airways miles to book a trip on United, if the US Airways flights are sold out. If that doesn't work, be sure to check with the other carrier, since the two partners might have access to different award inventory on the same plane.

A final strategy is to be realistic about the award you're trying to get. Improve your odds by traveling at an off-peak time of the year, when in many cases you'll be able to use fewer miles for the same seat. Or choose a less popular destination that has less demand for free travel; American and Delta are among the carriers that publish lists of "hotspots" that have plenty of award availability.

Sometimes, it's worthwhile to buy your ticket to your dream destination, instead of using miles. If you find a good deal to Hawaii, for example, you could earn 10,000 miles for the flight alone. When you pay for a seat, your account will still be brimming with the miles you didn't use for an award. Then, when it comes time for your next vacation, you can trade in those miles for a free ticket or a first-class upgrade, which could easily be worth $1,000 or more.

Your goal with your frequent flier account should be to spend the least amount of miles for the highest-value award. When you let your miles just sit on the shelf, they're not worth a thing.