LOL, you know the saying: unlucky at games, lucky in love. But it is tricky to find planes that are unknown since this group is so diverse, different parts of the world, different types of aviation etc. I could send a few pictures over via email you could post that I'm pretty sure no-one knows
Or how about: Name That Airport using only a picture of the control-tower?
Velo: So it wasn't a Daimler I take it. Hmmm, Jaguar never did make airplanes to my knowlege and until WWII they were actually the Swallow Sidecar company (SS, which is why they changed it to Jaguar which I believe was a model-name they used once). Aston Martin is too young. Auto Union never made planes I think. I doubt it was Porsche either since that didn't exist that early as a company. I don't really think it could be from north-america since I don't think they made such planes back then but of course I'm no expert on that field so I could be wrong. How about Skoda?
Edit: I just thought of something, maybe I was tricked by the hint. I thought the company didn't make aircraft but maybe it was airplane. Is it an old Igor Sikorsky design?
Frank