The same tech drawings can be found on the internet. They are not copyrighted either because they belong to Messerschmitt not that guy on Ebay who claims they are copyrighted. How can he copyright something that is not his.
Thats what I think is funny about that guy. The stuff that he claims is copyright is not his and not copyright. He did not take the pictures, he did not design the aircraft...
Why pay the guy for something that is not his anyhow?