[LoPo]

Targeting ground targets is a bit difficult, but you can switch to bombs and your targeting system will track targets with a square or triangle depending on which plan you are flying. A good thing do even if you are out of bombs and haven't flown back to reload, is to toggle between bombs and missiles, using the bomb targeting to light up targets with your guns. I've gotten many kills this way because the opposition is driving a buggy or sitting in the turret of a tank, or straight up blown the vehicle up.

Give it a try, it really helps on the darker maps or maps with a lot of shadowing.