I principali CRS sono attualmente quattro: SABRE (American Airlines), APOLLO (United Airlines), AMADEUS (AF, SAS, Lufthansa, Iberia), GALILEO (BA, KLM, TAP, Sabena, Swissair, Alitalia, Aer Lingus).
Les principaux SIR sont actuellement au nombre de 4, SABRE (American Airlines), APPOLO (United Airlines), AMADEUS (AF, SAS, Lufthansa, Iberia), GALILEO (BA, KLM, TAP, Sabena, Swiss Air, Alitalia, Aer Lingus).