A World of Mileage Earning Opportunities & Free Travel Awards. With Alaska Airlines and their airline partners, members have a total of 15 airlines to choose from for mileage earning and award travel, including more major U.S. airlines than any other frequent flyer program.

Miles can also be earned in a variety of other ways—including car rentals and hotel stays.

• Mileage Plan Miles are "immortal" and never expire (subject to member's account remaining active for 3 years).
• If no mileage is credited to an account during the first nine months after opening, or if an account is inactive for longer than 3 years, the Alaska Airlines Mileage Plan reserves the right to delete an account and reassign the number.

Alaska Airlines Web Site