Article 3
Functional airspace blocks
Member States may maintain the cooperation and coordination within the airspace of functional airspace blocks formerly established under Article 9a of Regulation (EC) No 550/2004 with the view to fostering the performance of the air traffic management network within the Single European Sky, in particular by submitting joint performance plans in accordance with Article 23(7) of this Regulation, provided that this does not affect the efficient implementation of this Regulation and that costs related to functional airspace blocks are reported separately, as part of the data to be provided under the charging scheme set out in Articles 29 to 36 of this Regulation.