A typical characteristic of legacy carriers is that they usually provide higher quality services than a low-cost carrier; for example, a legacy carrier typically offers first class and business class seating, a frequent-flyer program, and exclusive airport lounges.[2] Many legacy carriers are also members of an airline alliance through which they agree to provide those services to each other's passengers. Also, legacy carriers generally have better cabin services, such as meal service and in-flight entertainment.

The term 'legacy carrier' has generally not been used outside the United States. Many other countries have long-established flag carriers that are or were historically owned by or often given preferential treatment by their national governments. The national airlines occupy a position roughly equivalent to the American legacy carriers on quality of service and membership in international alliances compared to newer low-cost carriers. None of the American legacy carriers is an official flag carrier of the United States.

Since the Deregulation Act, many legacy carriers have folded or merged with other carriers. Those that survived now benefit from the fact that low-cost carriers no longer hold large cost advantages over the major legacy carriers.[3][4] There are currently three U.S.-based legacy carriers left that operate transcontinental and overseas route networks