There is often less in the ‘Copy” issue than meets the eye…

Often planes designed for the same mission will come out looking alike due to a third-party (airline or military) requirement.
Witness the DC-10 and Lockheed L-1011.
I believe it was American Airlines that wanted a wide body transport ideally with “more than two, but fewer than four” engines for internal U.S. use.

At another extreme (and the subject of a recent thread) …the Auster AOP 9 and the Cessna Bird Dog.

Sometimes “the state of the art” dictates design…early jet engines needed a lot of air so they had a front “open mouth” intake…combine that with swept wings and you’ll get something that looks like a F-86, MiG-15 or Mystere…and to my knowledge, nobody copied anyone (except for the MiG engine).

And just because the Germans had paper plans for the outside of advanced weapons doesn’t mean all the internal and systems designs were done…or that they had even detail designs for the fuselage. An external rendering of an aircraft doesn’t mean it’s designed. There are thousands of drawings involved to design an entire aircraft.

What the drawing do tell us is the Germans were thinking of designs and ways to solve problems when other countries/companies hadn’t even discovered there were problems to be addressed.