Secondary hub airport location selection for Turkey

The air transportation system looks like a network in which airports are represented as nodes and flight routes as links. The degree of connections between airports are defined as air connectivity. Airport connectivity is becoming an increasingly important issue with the increasing competition environment after liberalization in the air transport sector. Thanks to Turkey's advantageous geographical location that forms a bridge between the Asian and European continents, and the hub and spoke system applied to the network structures of the airline companies operating in Turkey, the city of Istanbul has become a major transfer point. However, considering the increasing demand for air transportation, population growth, tourism and trade volume, capacity constraints of airports and existing and ongoing transportation infrastructure investments, it is evaluated that the air connectivity will increase and the local market will develop more with the establishment of a multi-hub network structure in Turkey. In this study, in order to contribute to the development of a multi-hub air transportation model in Turkey; A literature study has been conducted on the hub location problem in air transportation, and a hub location model has been developed considering the factors affecting the airport connectivity. GAMS software was used for model solution. Different scenarios were produced and solution results were evaluated in order to measure the effects of high speed train accessibility, green airport applications and the Covid-19 pandemic.