BookYourAward.com founder Gary Leff—who has mastered the art of snagging hard-to-get international award seats—shares his expertise on some of the most popular and versatile programs, to help you determine which one is right for you

AIR CANADA AEROPLAN
Use your miles for flights on: Continental, United, US Airways, Air China, Air New Zealand, ANA, Asiana, Austrian, Lufthansa, Scandinavian, Singapore, South African Airways, Swiss, Thai, and 11 more international partners.
Main advantage: This is arguably North America's best mileage program. Air Canada's membership in the Star Alliance gives you the greatest number of airlines and flights to use your miles on, and Air Canada's routing rules are very generous and award flights come cheaper than they do via other Star Alliance partners. A business-class ticket from New York to Paris, for instance, costs only 80,000 Aeroplan miles—as opposed to 105,000 on Continental or United.
Main drawback: Miles expire after 12 months unless there is activity in your account. (Keeping your account active is easy; you can transfer mileage from an American Express account, for instance, or make a purchase via Aeroplan's eStore.) Even with activity in your account every 12 months, miles expire after seven years.
Best for: Those who fly Star Alliance carriers (e.g., Continental, United, and US Airways) and whose award goal is international flights in first or business class.
Insider tip: Don't use your Aeroplan miles for flights on Air Canada because you'll have to pay fuel surcharges; use them for flights on Air Canada's partners, which don't impose fuel surcharges. And don't get the Aeroplan MasterCard: Instead carry a Starwood Preferred Guest American Express Card (see page 48), since you can convert the Starpoints you collect into Aeroplan miles and get 5,000 bonus miles for every 20,000 you convert.

ALASKA AIRLINES MILEAGE PLAN
Use your miles for flights on: American, Delta, and 12 more Oneworld and SkyTeam partners, including Air France, British Airways, Cathay Pacific, LAN, and Qantas.
Main advantage: You can combine the miles you earn from flying both American and Delta. If or when you fly on Alaska Airlines itself, award availability is generous, and upgrades and elite status are relatively easy to attain. And Alaska Airlines offers one-way awards (American does too, but Delta does not).
Main drawback: Alaska Airlines' routes are pretty much limited to the West Coast, and the elite status you might earn can be used only on its flights.
Best for: Those who live on the West Coast (where Alaska flies) and who fly American and Delta but are not earning enough miles with either carrier to get the free flights they want or to reach elite status. Say your home airport is Los Angeles, where American and Delta both have a substantial presence, but you fly neither airline enough to obtain elite status. If you credit those miles to Alaska, you can reach elite status faster and get a greater choice of award seats than you would through American or Delta alone.
Insider tip: The Alaska Airlines Visa Signature Card, issued by Bank of America, gives you a $99 companion ticket every year, for use on Alaska Airlines in any fare class. Want to fly from Washington, D.C., to Maui? Buy a first-class Alaska Airlines ticket from D.C. to Maui via Seattle and you can fly someone else in first class with you for just $99.