This volume discusses various institutional, legal and operational aspects related to the provision of air navigation services, taking particular consideration of the current implementation of a new generation of communications, navigation and surveillance systems for future air traffic management (CNS/ATM). The primary intent is to critically review the current mechanisms for international co-operation in this field. Particularly in Europe, many efforts have been undertaken to enhance air traffic management by harmonization and integration of national developments but many parties claim that these are still insufficient and the processes are still dominated by the individual States. Furthermore, the established global standardization mechanisms by ICAO are increasingly challenged by the swift technological developments and implementation plans on a regional rather than global basis.