Frequent flyer secrets revealed

HOUSTON (KTRK) -- More than 300 million people belong to frequent flyer programs, stashing away miles in hopes of a free flight.

It's no secret that with limited seats and blackout dates, using those miles can be frustrating.

Consumer Reports checked out nine frequent-flyer programs and found big differences.

To find out just how big those differences are, they asked staffers to try booking round-trip tickets using their frequent-flyer miles. They tried using:

- Alaska

- American

- Delta

- Frontier

- Jet Blue

- Southwest

- Spirit

- United

- U.S. Airways

They searched for a seat on the five most popular U.S. routes for flights that departed in three days, one month, and three months.

"Options were often limited. Our results are just a snapshot in time, but we had the most choices on Delta, followed by Southwest and U.S. Airways," said Mandy Walker with Consumer Reports.

The deals also varied greatly.

"Spirit required the most miles for the routes we checked, followed by U.S. Airways. And they both charged the highest booking fees, more than $100 for last-minute travel," Walker said.

The best mileage deals were with Alaska Airlines, followed by JetBlue, American, and Delta.

Consumer Reports found you are usually far better off booking early. For example, on Southwest's Chicago to New York route, a round-trip ticket went from around 17,000 miles a month before departure to more than 77,000 for a flight three days away.

"On short notice, United was the only one that sometimes lowered the number of miles needed to book a seat," Walker said.

Whatever you do, Consumer Reports says don't hoard frequent-flyer miles. You run the risk they'll expire.

If you can't book a seat using miles, try calling the frequent-flyer service desk. Agents can sometimes find seats that you can't.

Here are nine ways to maximize your rewards and increase the odds that you'll land a seat:

1. Try to book early - Booking at the last minute is sometimes unavoidable, but it will usually cost you more miles for economy class. Most airlines make seats available about 330 days before departure.

2. Check the cash amount - Before you book, compare the number of miles you'd have to spend with the dollar amount the ticket would cost. Look for fares that work out to more than 1 cent per mile.

3. Consider upgrades - If you can't find an awards seat on a flight, consider buying an economy seat and using points to upgrade. Spending 15,000 miles to upgrade a $189 economy class fare to a $1,500 business class fare (about 9 cents per mile) is a great deal!

4. Call the airline - Agents can sometimes find seats that you can't, or they might be able to override capacity controls. You'll be charged a fee (often $25) but only if you book.

5. Get a card - If you're loyal to a particular airline, it makes sense to sign up for its card to maximize your earnings. Look for 40,000 to 100,000 miles after the initial spend (usually in the first 3 months).

6. Don't hoard miles - Airlines can change their rules at anytime, increasing the number of miles it takes to book travel or even making it tougher to earn those miles.

7. Check out partner deals - Most programs will allow you to rack up additional miles when you also throw your business to its hotel, rental car, or retail partners.

8. Look for elevated status - If you travel enough to qualify for elite status, many programs eliminate blackout dates and/or increase seat availability. You may also be able to get free upgrades or checked bags.

9. Divide to conquer - On some flights, you might be limited to a maximum of two award seats. If you're traveling with family, you may have to fly on different planes to get freebies.