et's say you live in Washington state, and you've been saving frequent flier miles for a trip to Florida. It's time to book your flight now that you have 25,000 points. That's the number needed for a domestic round-trip airfare award. (Round-trip air to Hawaii or Alaska, from a domestic departure point, usually requires 30,000 points.) Soon you'll be on your way, right? Maybe, but there's a lot to know before you get off the ground--if you'll even be able to take off when you want. Frequent fliers find getting free seats has become increasingly difficult. And, evidence suggests it's only getting harder--for everyone from high-mileage business travelers to conscientious budget fliers. Recently, three major airline alliances resulted in mergers of frequent flier programs. The new alliances are American and US Airways, Delta and United, and Continental and Northwest. On the surface it sounds good. Alliances offer more destinations and new opportunities for pooling miles. But not so fast. More choices do not mean more free seats. In 1997 the airlines awarded two million frequent flier miles--three times the number of free seats awarded 10 years ago. So what's the problem? Simply put, it's a numbers game. More than 57 million people have frequent flier accounts, but only about 7% of seats on popular itineraries are available free. From the airlines' perspective, if they can sell seats, they're not going to give them away. And, airlines often change the rules on already tight restrictions, making it more difficult for frequent fliers to cash in awards. Interestingly, consumers redeem only about 75% of all frequent flier awards. Reasons range from consumers forgetting they have miles, to not having time to use them, to not being able to find free seats when they want them. In the future, consumers likely will redeem even fewer frequent flier miles as more companies compete for fewer miles.

More than 57 million people have frequent flier accounts, but only about 7% of seats on popular itineraries are available free.

Improve your odds--eight ways to get what you want 1. Be flexible. This is the most important rule. If you want to go to Colorado between Christmas and New Year's, you'll probably have a hard time finding free airfare. On the other hand, if you're flexible and can book that ski vacation between January and March, chances are you'll find dates you can use. 2. Book early. This is the second most important rule. In the U.S., 500 routes are considered the most popular. That sounds like a lot, but not when thousands of other travelers are hoping to fly at the same time to the same place. According to the July 1998 issue of Consumer Reports, the airlines "booked 152,000 fewer award seats last year on the routes frequent fliers most wanted to travel." Most of the time booking early means you must call the frequent flier desk of your designated airline at least two months to three months in advance. But if you're using frequent flier awards to such popular destinations as Hawaii, you'll need to book as early as six months to 12 months in advance.

3. Look for last-minute seats. The number of frequent flier seats on a given plane depends on supply and demand. If a flight isn't sold out, the airline may offer more free tickets. Keep checking with the airline as you get close to your preferred departure date. Or check with Southwest Airlines--it gives free seats to frequent flier members any time space is available. 4. Know your way around "nuisance charges." The airlines know how to get you to pay more for that free ticket. Here are ways to beat the odds: To apply points toward a car rental, you'll usually receive a certificate. Allow about three weeks to receive this award. With 5,000 reward points, for instance, you'll receive a certificate worth $50. You can get an emergency certificate, if you need a rental car fast--typically for an additional $35 fee. If you pick up your ticket the same day you book your flight, it easily will cost you $60 or more. If you book a frequent flier flight, then can't use it, you can redeposit the points into your account. But you'll pay $35 or more.

Airlines know that when frequent fliers book a seat they often pay for a companion's ticket.

5. Know where you can get extra points. Frequent flier programs constantly award bonus points. Watch for announcements in your program's statements or call the airlines and ask about current promotions. 6. Compare prices. Before using your miles, find out what it would cost to fly the same route on a low-cost, advance-purchase coach ticket. Use this easy formula when comparing fares: Take the cost of the coach ticket and divide it by the number of miles needed to get the free seat. If the answer is one cent or less per mile, you're better off buying the ticket. If the value is more than 1.7 cents, take the free ticket. To maximize awards, many frequent fliers save points for trips abroad. This is where you often can get a lot of "bang for the buck." For instance, you can use your 60,000 points (mileage necessary for most overseas round-trip tickets) for a round-trip ticket between London and Chicago, but you can travel much farther, to North Africa, for instance, on the same number of points. Here again, it's best to compare fares. If the airline has a sale between Chicago and Singapore for $500, you're better off saving those flier points.

7. Don't lose points because they expire. If your frequent flier miles are in an airline account, they usually expire after three years. If you haven't used your miles close to the expiration date, ask the airline to issue you a certificate. This way your miles usually are good for an additional year. At least one airline offers the option of an automatic one-year extension on expiring miles (a balance of at least 20,000) by accessing its Web site, calling its 800 number, or sending back the top of the statement. 8. If an airline won't release seats, speak to a supervisor. Many travelers don't take their complaints far enough. If you have a record of consistently flying this airline, your efforts may pay off. Airlines know that when frequent fliers book a seat they often pay for a companion's ticket. If that's your intent, make it known--tell the airline it stands to lose the business of a paying customer if it can't accommodate you. Airlines now are flying at record capacities--usually at 70% or more. Yet, the number of frequent flier seats hasn't increased. Savvy fliers know how to get what they want by combining knowledge with a lot of patience and planning.

Before using your       miles, find out what       it would cost to       fly the same route       on a low-cost,       advance-purchase       coach ticket.