Legacy carrier

A legacy carrier, in the United States, is an airline that had established interstate routes by the time of the route liberalization which was permitted by the Airline Deregulation Act of 1978 and was thus directly affected by that act. It is distinct from a low-cost carrier, (a term fostered as a form of disparagement against post deregulation start-up air carriers, and the traditional airlines once heavily unionized work groups) which in the United States are generally new airlines that were started to compete in the newly deregulated industry.

Typical characteristics of legacy carriers are that they provide a higher level of services than a low-cost carrier; for example, a legacy carrier typically offers first class and/or business class, a frequent-flyer program, airport lounges, and is a member of an airline alliance through which it has partners that agree to provide these services to its passengers as well. Also, there is a higher level of services in the cabin, such as meal service and in-flight entertainment.

Due to competition with low-cost carriers since the Deregulation Act, many legacy carriers have folded or merged with other carriers. Among the legacy carriers with nationwide route networks, there will only be four left once United and Continental consummate their merger.

• Delta Air Lines
• American Airlines
• United Airlines
• US Airways

Other American legacy carriers not included in the "Big Four"

• Alaska Airlines
• Hawaiian Airlines

Defunct carriers include:

• Continental Airlines, merged with United in 2011
• Western Airlines, merged with Delta
• Trans World Airlines, merged with American, 2001
• Pan American World Airways
• Northwest Airlines, merged with Delta, 2008, brand retired in early 2010 as it completed its merger with Delta
• National Airlines (NA)
• Eastern Air Lines
• Braniff International Airways
• and some others.