Abstract: A computer system and a method for determining a travel scheme minimizing travel costs for an organization, where the organization expects to purchase travel trips for a plurality of travelers for a plurality of travel links. Each travel link comprises a travel origin and a travel destination, and is served by at least one of the carriers. The system comprises a data input device for receiving travel information relating to the carriers and the links, a data storage device for storing the travel information received by the data input device, a processor, and a data output device. From the travel information, the system constructs an objective function representing a travel cost to the organization to purchase travel trips for the plurality of travelers for the plurality of predetermined links, and a set of constraints comprising restrictions relating to the objective function.