Giraffes were hungry.
The gorillas were silly.
All big cats sleeping.

How to unlock Heat Seeker missiles in Battlefield 3, a photo by lucky_clover on Flickr.

Finally! So I spent way too much time trying to get these buggers unlocked! It’s a combination of luck and skill my friend. The first key is to master flying and how to dodge missiles. Basically you need to keep moving and not in a straight line comrade. Learn how to maneuver the jet and then come in from a distance to perform strafes. Once you get flares unlocked staying alive longer in the jet gets easier. The fun begins in dogfighting with guns and the secret to that is short bursts. Do a Viking takeoff and go to outside cockpit view and kick it over into a dive and look for some enemy attack helicopters. Go in blazing and take them down. You get the heat seeking missiles unlocked at 400 points! Good luck!