Regulation of air transport is one of the most fundamental issues of international aviation and is therefore of great interest to all airport operators. Regulation policies affect the volume and character of air transport services and thus have a major impact on airports. Furthermore, the availability of adequate levels of high quality, safe and secure airport facilities is critical if the goal of the liberalization of air transport is to be achieved. Until recently, scheduled passenger transportation was heavily regulated in most countries at both domestic and international levels. Domestically, entry into the air passenger business, initiating service on specific routes, operating aircraft above given sizes, reducing or discontinuing services, investing in airlines, establishing and applying various categories of passenger fares is subject to a detailed set of rules and regulations. International regulations compound these domestic rules. They govern the conditions of entry and ownership, the selection of operable destinations, and the freedoms to set capacity and fares on international routes, which represent more than 60-70 per cent of all passenger-kilometers performed in most countries, with the exception of continental size countries. The policies and regulations which have governed the air transport industry for several decades have various motivations (including safety, national prestige, national defense, regional and urban development, environmental sustainability, public service and other non-commercial objectives) specific to each country. However, there is a growing consensus that unnecessarily restrictive regulations may have led to significant losses of economic efficiency, and thereby failure to secure low-cost air transportation to the largest possible proportion of the population - the ultimate objective of air transport policies. Recognizing these shortcomings, several governments have initiated reforms in the past two decades.