The field of the invention relates to methods, servers and computer program products for inferring which fare classes are available. There is provided a method of inferring fare class availability for a specific flight or flights by: (a) receiving observable, live bookable prices for that flight(s), in which that price information is not accompanied by complete fare class information for those flight(s); (b) comparing the observable, live bookable prices with a set of prices calculated from stored data, such as valid itinerary data, fare data such as FROP data, and tax/ surcharge data; and (c) determining which fare class was used in the observable live bookable price by determining which fare class was used in the calculated price that matches most closely to the observable live bookable price.