The Surface to Air Missile, or SAM, is an unmanned guided weapon system in Grand Theft Auto: San Andreas. Four sites are located around Area 69 and two in the Easter Basin Naval Station on the LHD-069 aircraft carrier, both of which are no-fly zones.
SAM sites are silos of anti-air missiles installed on pods that use radar-targeting system to fire heat-seeking missiles. They are used to defend restricted areas from aerial intrusions.
If the player flies any aircraft, or the jetpack, near or over these zones, several heat-seeking missiles that track the movement of the player's vehicle, will be launched, the player can hear a warning sound and a small red blip on the radar. These missiles can severely damage the airplane's wings or engine (or the player, when using a jetpack), making it harder to fly. Depending on the durability and health of the player's vehicle, a few to some direct hits will destroy the vehicle and kill the player if they do not eject.
The launchers can be temporarily destroyed and will respawn once the player is far enough away from them. During the mission Black Project, the sites around area 69 can be disabled temporarily from within the underground labs for the rest of the mission. Excluding the first part of the mission Vertical Bird, the SAM Sites on the aircraft carrier in Easter Basin are permanently disabled and will not shoot when the player flies over or near the Naval Station (this is probably a bug or intentional as the ship is docked, unlike those at area 69, that function normally).
These sites can be destroyed by simply shooting, using explosive weapons or rockets and even melee attacks, then destroyed, it will explode but it won't harm the player.
Like other heat-seeking missiles, the SAMs can be deterred by using the Hydra's secondary fire, which launches flares.