In the United States, a legacy carrier is an airline that was once economically regulated by the Civil Aeronautics Board (CAB) during the period of airline regulation 1938–1978 or can trace its origin to one that did. The CAB was a now defunct federal agency that tightly controlled almost all US commercial air transport during that period. As related below, many features associated with the legacy airline business model were actually developed not during the regulated era, but instead in the first decade or so of the deregulated era, as legacy carriers adapted to an unfamiliar competitive environment.
While the term "legacy carrier" is most often used in a US context, it is possible to speak of legacy carriers elsewhere, since tight airline regulation was once the global norm and following US airline deregulation, many other countries went through some kind of airline deregulation. Non-US carriers with origins that precede liberalization can be viewed as legacy carriers. For instance, in Europe, flag carriers such as British Airways, Air France, KLM, Iberia, and Lufthansa, (with origins well before the liberalized era) can be viewed as legacy carriers in contrast to airlines such as Ryanair, EasyJet, Wizz Air, and so forth.
