some of the missions are escape and evade. you dont want to engage the enemy,,,know there is one of these in britian...and one in russia. some are escort missions where you have to protect a certain plane or a flight. in those just hang off their 6 a couple hundred yards and pick off any ea that line up on them. on the combat missions you can complete them by simply surviving but 2 things will happen...or shall i say NOT happen. 1. your rating stays low..2. you dont unlock trophies. some of the trophies depend on you knocking off a plane(s). there is a trophy lists.
http://www.ps3trophies.org/game/il-2...prey/trophies/
and airplane unlocks
http://cheatcc.com/ps3/il2sturmovikb...eatscodes.html