This study aims to locate optimal global hubs for an airline or a group of airlines to cover international flights between countries. Despite designing a hub network for regional flights, designing a hub network for international flights is considerably different because of the high frequency of medium-, or long-haul flights. Accordingly, designing a hub network without considering the fleet size and diversity is impossible. This study proposes three airline Hub Location Problems (HLPs) in a global scale with the following considerations: Ι) an HLP providing the possibility of operating the multi-leg flights by a limited fleet size, ΙΙ) an HLP respecting consideration (Ι) with the possibility to increase the efficiency of the fleet by taking the aircraft characteristics into account in the design of the hub network, and ΙΙΙ) an HLP respecting considerations (Ι) and (ΙΙ) with the possibility of fleet planning. These models are solved for several instance networks, being up to 300 networks, and compared with an HLP without these considerations. The results mainly demonstrated that ignoring the aircraft characteristics in an HLP can generate an inefficient or infeasible hub network configuration. In addition, the problem of a real international flight network was solved and the insights regarding designing an optimal hub network and fleet configuration were presented.