Blazing Angels

This achievement is earned in campaign mode, in which you need to earn the rank of Colonel. Colonel comes after Leuitenant Colonel which is after Flight Officer. You should earn this rank when you're are halfway done beating the game for the second time. It's said that this achievement is dependant on your kills and that you need roughly 700 plane kills, 700 Turrets/bunker/AA guns and 100 naval units. These stats will also vary between players, as the game also factors in the time it takes you to finish each mission as well. Depending on how quick you are in the game, you can possibly get away with less than the kills specified, or well over.