Liberalization of regulatory policy on international air transportation through the use of bilateral and multilateral open skies agreements contributes to a business environment that presents air carriers with the opportunity to take advantage of greater access to aviation markets world-wide. Chapters in this volume of Advances in Airline Economics provide in-depth analysis of open skies agreements. In addition, contributions present empirical analysis of the effect of greater availability of international air transportation services on air fares, export flows, operating efficiency, and passenger demand for international flights. The influence of international airports on local metropolitan areas' economic development is also examined. Regulation of international air transportation, however, is not limited to the erosion of entry barriers. Companies providing international air transportation services also face restrictions on pollution emissions. This volume provides a more complete analysis of the economics of international air transportation by presenting research on the costs borne by air transportation companies due to pollution regulation in Europe, Australia and New Zealand.