Source: IATA. RPK: Revenue Passenger-Kilometers.
Until the 1980s, airline companies were strongly regulated by governments with protected routes and the prevention of foreign ownership. With deregulation initiated in the United States in the 1980s, a reorganization of the airline industry has occurred. The main trend involves alliances between airline companies to the point that some have almost merged. Most large airlines, and many smaller ones, have joined alliances in order to broaden their market presence commensurate with a global economy. In 1998, about 500 alliance deals existed between airline companies, Star Alliance, SkyTeam, and OneWorld being the most important (23%, 20% and 18% of the global revenue passenger-kilometers respectively).