https://eur-lex.europa.eu/

Compilation of the regulations for balloon flights (Balloon Rule Book):

EU regulations for balloon flights

This is the case and this possibility is regulated in Germany in the Basic Law for the Federal Republic of Germany:

GG §23 (1) With a view to establishing a united Europe, the Federal Republic of Germany shall participate in the development of the European Union that is committed to democratic, social and federal principles, to the rule of law and to the principle of subsidiarity and that guarantees a level of protection of basic rights essentially comparable to that afforded by this Basic Law. To this end the Federation may transfer sovereign powers by a law with the consent of the Bundesrat. The establishment of the European Union, as well as changes in its treaty foundations and comparable regulations that amend or supplement this Basic Law or make such amendments or supplements possible, shall be subject to paragraphs (2) and (3) of Article 79.