The wings look good!
Maybe goint to the shaders attribute editor and enhance the hardware shading will solve your textuing disappearing, in combination to go looking for it on other parts of the aircraft.
But, I never dare texture nurbs
About that spitfire, hrm I dont know where it is right now. But I'll contact you in distant future unless you really need this.
Else you are sure to find drawings of spitfires on the web. Just takes a little time to find the ones you want.
I do not support Bush! Nor Saddam! Long live UN!