Airway transportation is the fastest type of transportation. Advances in aviation technologies, planes’ increased speed, and the large number of companies in the airway transportation sector cause rising competition and lower prices. In such an important sector, each type of investment has to be feasible and logical, e.g. airport location, aircraft purchase, services, crews and their assignment, etc. Whether purchasing, renting or chartering aircraft, airline companies’ biggest cost is the maintenance of their fleet. For this reason, in this paper we study the purchase of aircraft in a Turkish airline company using fuzzy numbers. Multi criteria-decision making techniques, fuzzy ANP and Choquet integral methods are used for evaluation and the results of both algorithms are compared by using fuzzy AHP.