WW2 USAAF figure sets are pretty thin on the ground. There the Aifix set, one from Prieser and a few from CMK. The only one with a figure sitting on the wing is this one.
http://www.hannants.co.uk/product/CMF72039
But that looks more like a pilot figure. Your only other option would be a conversion with the kneeling figure here.
http://www.hannants.co.uk/product/CMF72114
Or you could get the Airfix set and convert one of those. It would be a bit more work, but the set is cheaper and they are a bit easier to work with IMHO.
I am a Norfolk man and i glory in being so
On the bench: Airfix 1/72nd Harrier GR.3/Fujimi 1/72nd Ju 87D-3