FRESNO, Calif. (KFSN) -- Americans have accumulated billions of frequent-flyer miles. But often they're stymied when they try to redeem them for free flights. Consumer Reports did some exhaustive research and has insider tips on how to get airlines to give you the free travel you've earned. It analyzed the latest data from the Department of Transportation and found Southwest to be the most generous carrier, giving away 11.5 percent of its seats. Jet Blue is the stingiest, giving away only 4.5 percent. Others fell in between: United, 9.8 percent, American, 9.4 percent, and Delta, 8.8 percent.
Consumer Reports has these useful tips for redeeming your miles:
Book several months in advance when there are more awards seats available. However, last-minute searches can also work because people change their plans and seats become free.
If you're hoping to travel overseas and there are no awards seats available on your U.S carrier, check their foreign partners. You may be able to get one of their award seats. For instance, American's partners include British Airways. Delta has Air France and United has Lufthansa, among others.
Don't jump on just any free seat. You don't want to waste your miles on a cheap trip. To figure out if it's worth it, divide the price of the ticket by the number of frequent-flyer miles you're spending. If the result is less than a penny, you're better off paying cash.
If you don't have enough frequent-flyer miles for a roundtrip ticket, many airlines now allow you to book one way with miles and pay for the return with cash.
If you're short of miles for a trip you want, don't buy them. Frequent-flyer seats you purchase are not a bargain.
Tap or click to download more information.