Nope, not German (although the company names (only two of them) sound like it, but the company-name is usually just written as their initials). I must say I thought you guys/gals would've easily guessed it by now. What if I give a hint that I've seen one (perhaps the very one in the photo since not many were made) in real life?
Edit: Oops, I hadn't noticed there was a whole extra page of posts until after I posted my reply to Gulf's post. Actually come to think of it maybe I did, then I might as well just spill the beans and find a different one, an easier one.
It's a danish "KZ IV" Kramme og Zeuthen model 4. And it's not the swiss flag, it's a medic symbol. It was costum-built to be used by Zone-Rescue (later combined with Falck rescue which exist to this day and also work with the county with fire-engines and ambulances) to pick up sick people from the many small islands we have.
http://www.flymuseum.dk/fly/flytekst/kz4.phpBtw, the high-altitude plane is not the Gossemer Albotros is it? Or was the one with the guy powering it by a bicycle inside?
Frank