In March 2004, the legislative package SES I came into force. The package consists of a Framework Regulation creating a Single European Sky and three more regulations regarding the provision of air navigation services, the organisation and use of airspace and the interoperability of the European air traffic management network. This legislation is directly applicable in each EU Member State, i.e. it is equivalent to national law.

The Framework Regulation establishing a Single European Sky underscores the significance of the European Community joining the international organisation EUROCONTROL. As far as possible, these two rule-making bodies should not encroach on each other's separate and distinct areas of responsibility. The standards and recommended practices of the International Civil Aviation Organisation (ICAO) are also taken into account.

The objective of the Regulation on the Organisation and Use of Airspace is to create a more integrated airspace. Furthermore, establishing common procedures for design, planning and management increases the safety and efficiency of cross-border air traffic management.

The Regulation on the Provision of Air Navigation Services defines common rules for performing these services. A uniform certification system has been established to ensure the quality of air navigation services. Certificates are issued by a national supervisory authority, which defines and regularly monitors the rights and obligations of air navigation service providers.

The Regulation on the Interoperability of the European Air Traffic Management Network aims at ensuring the compatibility of systems and their constituent parts and procedures as well as the coordinated introduction of new technologies.