Secret projects - innovation

[urilch.von]

I have a question. Is the latest HOI IV can be under the tree technology made eg. Aircraft vertical take-off and landing (Focke-Wulf Triebflügel) or helicopters (Flettner Fl 282)?
How will the development of non historical projects?

 

[SpanglishEmpire]

There are a few screen shots of aircraft tech screens and the secret planes are greyed out, Though I am pretty certain that these are only jet variants of the various types.

It will definitely be able to do this in a mod though.