Not Schleswig-Holstein. It is in the same area as my previous one from WWI.
It is no longer an aerodrome so it's much harder to find, so to help <-------- is approx. north on the previous two photos.
There was a very early battle (Aug 1914) in the area (that'll have you thumbing through the history books). There seems to have been a fair amount of action in the first month of the war.
I have found some photos of the airfield on an auction site - but only when searching under the German name.
edit: my modern photo is a screenshot from Bing Maps as the "landing circle" is visible here, whereas it is not so pronounced in GE.