The largest airport by far is Amsterdam Airport Schiphol, which is the third largest in Europe. Smaller airports with scheduled passenger service are Rotterdam The Hague Airport (formerly known as Zestienhoven), Groningen Airport Eelde, Eindhoven Airport and Maastricht Aachen Airport. De Peel, Valkenburg and Soesterberg have been closed as a military airports and are now mainly used by gliders.