Frequent flyer programs are essentially a contract between you and the airline, and accordingly are subject to the same set of rules as any contract. In practice, however, this means that the airline pretty much dictates the terms and you can either agree and signup or not. This also means that the airline will usually state that they can change the rules of the program at almost any time with limited or no notice. Accordingly, frequent flyer programs are seen more as a bonus than an obligation. Because airlines reserve the right to make changes to their programs, sometimes on short notice, things to look out for .