Another useful site is the gateway scenery map. Airports in the current release of XP appear in blue or orange, airports available for download at the gateway appear in red. you can also filter for 3D airports only (i.e. ones with buildings), water runways, helipads, etc. It's reassuring to see the number of blobs on the map when you apply the 3D filter now - and Germany is absolutely covered thanks to Jan and his friend. Vielen dank!
http://x-plane.cleverest.eu/