Silvaire,
The way the system has settled in Europe is that "sport" aviation is represented by national aeroclubs, microlight clubs, gliding clubs, etc. They are collectively represented at a European level by an excellent organisation called Europe Air Sports (EAS). AOPA has its "centre of gravity" in the certified powered flying world. AOPA is the second of the two bodies directly accredited to the European regulator.
The system works pretty well, and for all the myths, the two organisations work amicably and effectively together.
brgds
421C