Considering the Spitfires excellent flight performance. In the late 30’s an Aerodynamicist, Canadian Beverly Shenstone, worked for Supermarine. He had spent a few years in Germany, working at Heinkel, doing a study of the aerodynamic properties of the elliptical wing shape. How ironic! These are a very even distribution of lift generated over the wing span, resulting in a reduction of span wise wing trailing edge and wing tip flow, leading to reduced vortex formation and thus very low lift induced drag. Problem is, this wing shape is complex, each wing rib, for example, is different. It is therefore difficult to mass produce. I believe Shenstone played a big part in the Spitfire having a double elliptic wing, possibly more so than Mitchell. Mitchell’s gift was that he wasn’t ego driven, anyone who had a good sounding idea, was listened to. The leading edge elipse, differs from the trailing edge elliptical shape, hence a double elipse. The saying Mitchell is reported to have said that the wing was “only that shape, to cover the guns”, was I think, a cover to divert from the real advantages of the wing shape. Apart from the planform shape, the other unique feature, was the wings remarkable thin frontal area. For it’s day it was a very thin wing, it was pretty unique. The Spitfire came within a hairs breadth of being cancelled, because the wing was so difficult to mass produce. Fortunately they didn’t!