Great attention is devoted, for example in Europe, to the development of regional airports, both to improve the congestion situation at the main hubs and to help the economic development of some decentralized areas. In this context, more actors can play an important role, as airport planners, air companies (including low-cost companies) and users (passengers and/or freight) that affect demand levels at airports through their travel choices. Furthermore, an efficient use of resources suggests we consider the role of existing regional airports before starting the building of new airports. In the USA more studies concern the analysis of airport systems (as in the Los Angeles area) in order to verify the role of each airport and the effects on the main, congested hub(s). In this light this book gives an overview of the main aspects of the potential development of regional airports, particularly the economic aspects, the role of the low-cost companies, demand modelling, the airport, airline and access mode of choices; and the relationships between hub capacity constraints and regional airports growth. Examples of different airports throughout the world are also presented as test cases with respect to the various aspects.