The Amaurotean Capitalist wrote:

"Scott M. Kozel" wrote:

The Merlin-engined Mustang only became a part of USAAF procurement
policy by means of British agency, and the Mustang also only existed
to start with as a result of British agency.

You keep calling it a "Merlin-engined Mustang" while in fact those
built by NAA utilized a Packard built engine that was a modifification
of the Merlin design.

I merely stepped into this thread when someone questioned why the P-51
was listed under USA aircraft.

It was an American aircraft; nevertheless it would not have existed
without British agency in terms of sponsoring the initial design
(although the technological and development work was almost entirely
done by North American) and furthermore it wouldn't have existed in a
Merlin-engined variant without the British pushing it upon the USAAF
at a time in mid-1942 when Arnold's fighter procurement policy was
subject to significant public misgivings.

Nevertheless it would not have existed in quantities that could have a
measurable impact on the war without U.S. final design and
manufacturing.

If there was no P-51 then some other design could have been developed,
such as the advanced P-47 being completed much sooner.