Heat Seekers

Heat Seekers are missiles that track heat sources (typically enemy vehicles). They differ from laser-guided, radar-guided, or wire-guided weaponry.

Singleplayer
Jennifer Hawkins, an F/A-18F co-pilot is able to fire them during the jet mission, Going Hunting.

Multiplayer
Heat Seekers is an air vehicle specialization that adds a secondary weapon designed to counter other air vehicles. Upon acquiring weapon lock, the pilot can fire up to two missiles that will continue to track the target. Only the vehicle's pilot may use the weapon. have a similar specialization in the form of Anti-Air Missile.

When activated, the pilot's HUD changes to a perforated targeting circle, showing its lock-on area. A Lock-On usually takes 3 seconds to lock, but with the upgrade Beam Scanning, the Lock-on will only take around 1 second. Each missile deals 45 of damage to enemy jets, dealing a total of 90 in damage if both of the equipped Heat Seekers connect. Since the jets' disable threshold is 50, one missile hit will not disable the aircraft, but striking with the Main Gun or second Heat Seeker will have it disabled.

Trivia

 * Unlike the fact that the main pilot is only the one capable of using Heat Seekers, Jennifer Hawkins, a co-pilot can use them in singleplayer mode. This can be a developer oversight though.