The schedules come from OAG, the fares come from ATPCO, and the availability (number of seats available on each flight in each booking class) comes either direc

The schedules come from OAG, the fares come from ATPCO, and the availability (number of seats available on each flight in each booking class) comes either directly from the airline or through one of the three GDS providers: Sabre, Amadeus, and Travelport. Technically, the schedules and fares are also available from the GDS, but only in an interactive format. ATPCO and OAG supply giant dumps of bulk data which is more suitable for offline processing and precomputing results.