Air transport and, in general, civil aviation, is an intensely regulated activity, in which international regulations, usually adopted within the framework of the International
Civil Aviation Organization (ICAO), European and national regulations coexist.

Specifically, in the European Union, competence on air navigation is shared between the Union and the Member States, as provided for in Articles 4.2 (g) and 100.2 of
the Treaty on the Functioning of the European Union (hereinafter TFEU), so that European and national regulations may coexist. Within this legal framework, the development of the common transport policy in the air transport mode has made it advisable to address at European level many aspects that were already regulated by the Member States, and to use the regulation as an instrument of harmonization.