The Single Sky initiative was launched in 2000 following severe delays during 1999. The European Commission tabled a legislative package at the end of 2001 which was adopted by the European Parliament and the Council in March 2004 and entered into force one month later.
This legislative package comprised four elements: the “Framework regulation”, the “Service provision regulation”, the ”Airspace regulation” and the ”Interoperability regulation”. Article 12§2 of the “Framework regulation” requires the European Commission to review the application of the Single Sky legislation and report periodically to the European Parliament and the Council.