...and submitted the SO.6020 when the French Air Force issued not crazy about the phrasing here. Suggest something like "and submitted a design proposal, designated SO.6020, in response to the French Air Force issuing..."
Rephrased.
The aircraft had have a speed "had have"? Maybe " had to have.
with planes to order "plans"?
aircraft satisfied the requirements. suggest "aircraft satisfied its requirements.
The aircraft was a metal-skinned mid-wing suggest "As built, the aircraft was a metal-skinned mid-wing..."
was the Heinkel ejection seat part of the original specification?
Yes.
Development
possibly due to the need to revise the air intakes shouldn't intakes be singular? Or should the first mention of intakes be plural?
Good catch.
Is there a link for SO.6025?
No.
I'm confused by the references to the SO.6021 in this section. On the one hand, it is a fighter prototype and on the other it is the proposed production version.
I think that I've clarified it now
Specifications
Is it necessary to recite the book titles here, can't [16], [17] just go against the "General characteristics" heading?