My comments on your shots:
#1 is overexposed and grainy. The reflection on the P-51 kills the shot, but the whites on this aircraft are also quite blown out.
#2 is a tad oversharpened. The colours are very lively, but I think the problem might be in the contrast, as Mike said. The bright background doesn´t help, also. Second edit is pretty similar as the first one.
#3 is a bit blurry, rather than soft, and in your first edit you sharpened it a bit too much in order to compensate that. The second edit on this one is even more jagged.
Hope it helps. Good luck with them!
"Faithless is he that says farewell when the road darkens." J.R.R. Tolkien