i don't think i mentioned this when talking about preferred loadouts so i will now.
when your flying a chopper, attack or scout, always be watching your air radar for jets. stealth jets will give you headaches but attack jets will fuck you up.
when it looks like a jet is going to be making a strafe run on you, fly towards it. i know that doesn't seem correct but its your best chance to take the least damage. by flying towards it you give the jet far less time to fire at you or get a missile lock.
also watch the way the jet is approaching. if he is coming from a downward angle, gain altitude as you fly towards him. if he is coming at a straight angle lose altitude. avoid the jet ram.
if your in the situation where you are dropping altitude beware of tanks. you make yourself a tasty target when you go low.
to further add to that, if you breifly have to fly low do so for as little time as possible. always assume there is 1 tank watching you and licking his chops as you fly low. you also have to be cautious of those Engis that are always licking their chops for a nasty RPG/SMAW on a chopper.