**1. Introduction**

The impact of air transport on the regional economy is of great importance, because it reflects to the economic profile of the region it serves and, in many cases, acts as a key driver of the socioeconomic development in regional or national scale. It is noteworthy that regions accessible to air transport services and connectivity to international markets, achieving essential economic benefits in terms of unemployment, business productivity and per capita income. Especially, for the tourism regions where the domestic income heavily depended on air transport and tourism performance, decisions on improving accessibility and the level of service are very crucial towards economic growth and social coherence.

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© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

The tourism industry of extremely competitive and fragile business environment leads tourism industry and authorities continuously encourage air transports for lower prices, more capacity and additional connectivity, promoting those as key drivers towards higher tourist demand and financial sustainability for both, transport and tourism sectors. In addition, the market tendency for growing leisure travelling, especially in holiday periods, along with the fast-changing technology and the continuing booming of e-commerce, resulting strong air transport growth and this tendency is estimated to continue in next decade, according to estimations and forecast delivered by global organization, national institutes and air transport authorities. Therefore, key counterpart of the effective regional strategic planning includes plans and decisions for investments to improve efficiency and grow capacity in air transport infrastructures. In other words, the timely and financially efficient allocation of capitals to air transport infrastructure is a key success factor on strategic planning process, affecting not just air transport and tourism sectors but also the regional economy as a whole.

However, the complexities of today's global economy and the uncertainty in investments to infrastructure projects with long payback period and high volatility in patterns such aviation and tourism, rising business and financial risks leading to high complexity in decisions, i.e., the decision for a new runway may take some decades. In addition, the large range of stakeholders that involved in the decision process is also an essential issue that must deal with. Considering the limitations of the real-world life, the decision-making key question deals with economic benefits subject to operational, financial and competition restrictions. Agencies, authorities and stakeholders need accurate estimations about the overall impacts on the regional and national economy to support investment decisions and define policies towards improvement of connectivity networks and accessibility infrastructures. Therefore, the assessment of any business scenario has to be supported by short- and long-term economic impact assessment providing clear message to decision-makers about the existing and future socioeconomic benefits in regional economy.

Key objective of this chapter is to quantify the economic impact of air transport on regions that heavily depended on outbound tourism. By a top-down analysis, the key trends of tourism and aviation market are highlighted, providing the linkage between these two industries. According to a systemic approach, the methodology concept and the modelling are presented, providing the framework for relevant case studies. Conventional wisdom is to provide an easyto-handle tool appropriate for relevant case studies and highlight key messages to decisionmakers, stakeholders and aviation authorities in their strategic decisions regarding air transport market development. The case studies presented in this chapter are related to Mediterranean region and focused on Greece, which is a very attractive summer holiday tourist destination.
