Black Ops like it’s predecessors has maintained the tradition of killstreak rewards. You kill certain number of enemies and you are rewarded accordingly depending upon your length of killstreak ranging from 3 to 11. The rewards for the corresponding killstreaks are:
3 Kills (Spy Plane)
Shows enemies on the mini-map. Can be taken down.
3 Kills (RC-XD Explosive RC Car)
Remote controlled car strapped with explosives.
4 Kills (Counter Spy)
Plane temporarily disables enemies mini-map.
4 Kills (SAM Turret)
Airdrop a placeable SAM turret that destroys aircraft.
5 Kills (Care Package)
Airdrop a random killstreak or ammo crate.
5 Kills (Napalm Strike)
Airstrike that covers an area in napalm.
6 Kills (Sentry Gun)
Airdrop a placeable Sentry Gun.
6 Kills (Mortar Team)
Target 2 locations to bombard with Mortar Strikes.
7 Kills (Attack Helicopter)
Call in a support helicopter.
7 Kills (Valkyrie Rockets)
Launcher with remote controlled rockets.
8 Kills (Blackbird)
Shows enemy position and direction on the mini-map. Cannot be taken down.
8 Kills (Rolling Thunder)
Carpet bombing airstrike.
9 Kills (Chopper Gunner)
Be the gunner of an attack helicopter.
11 Kills (Attack Dogs)
Attack dogs that hunt the enemy down.
11 Kills (Gunship)
Pilot an attack helicopter.