Hi,
Grump, in one point you be particular wrong:
You wrote this; "Your point of aspect ratio is linked to drag. Higher the aspect ratio the lower the drag.", but this only count for relative slow speeds(around up to mach0.6, depending to the aspectratio) and specialy flights with a positive aoa. A aspectratio of zero is of course the best for highspeed. Every rocket have, better sayed miss, such a wing.
At higher speeds a smal aspectratio is more usefull, cause the airmasses can get shifted away sideward, to avoid shockwaves, arrowed wings are even better.
But as i wrote, even the Me163(very smal aspectratio), neighter the Me262 was able to fly at speeds above mach0,85(without to crash cause the controlls stopped to work or the wings got off due to shockwaves).
Drag like we know it from speeds below mach0,6 is not that important anymore. To bring away the air masses to avoid shockwaves is important to minimize the drag at high mach numbers.
I realy doubt that a Spitfire wing, with its washouts and very old airfoil, and its fuselage, with the upward mounted engine, was able to reach such mach numbers.
The P51 semi laminar airfoil was much advanced at highspeed(compare the Vmax with same engine,and this although the P51 is much more heavy), but even this heavy plane(more downward thrust) wasnt able to dive that fast.
Of course we can believe what we want, but the probabilitys are not good for the default WWII Spit.
Greetings, Knegel