Not Loyal Yet? Our Guide to Becoming a Frequent Flyer

Few of us will compile 10 million frequent flyer miles like George Clooney's ruthless but dashing corporate downsizer in Up in the Air. And frankly, 100 percent free tickets and upgrades are increasingly difficult to obtain. But the programs won't be grounded, because trillions of miles have gone unredeemed, and airlines generate billions of dollars from brand cross-promotions on anything from accommodations to "affinity" credit cards (today over half of mileage points are earned without flying). But how to select the right rewards program?