Her's a quick attempt with the GIMP, just using Contrast/Brightness and a little sharpening:

The problem with this image is that the top part is way more exposed than the bottom. so I adjusted it in sections: the fender down, then the turret, then the subject... all so he wouldn't be so washed-out.
Didn't have much luck with the gamma adjustment, but that's still new to me...
Looking again, I see I over-sharpened him a little, and probably should've airbrushed the edge between him and the sky...
but not bad for about 5 minutes' work...
