I looked at the militaryphoto.net link but only skimmed through the other - just don't have the time to read it completely at the moment. My doodle reference was meant for aircraft only since the Germans cranked out dozens of paper concepts of all manner of shape and propulsion. Let a thousand monkeys bang away on a thousand typewriters and after a thousand years one is bound to reproduce the works of Shakespeare......

I don't think it was a mistake for the Germans not to continue across the channel after Dunkirk. The Royal Navy was intact at the time and would have been committed 100% to repel an invasion. The invasion of the Soviet Union was definitely a mistake and was a major, in fact the major factor in the defeat of Germany.