You unlock customizable killstreaks at level 10 and every about 5-6 levels you can unlock a different one. The killstreaks are:
3 Kills - UAV
4 Kills - Counter-UAV or Care Package
5 Kills - Sentry Gun or Predator Missile
6 Kills - Precision Airstrike
7 Kills - Harrier Strike or Attack Helicopter
8 Kills - Emergency Airdrop
9 Kills - Pave Low or Stealth Bomber
11 Kills - AC-130 or Chopper Gunner
15 Kills - EMP
25 Kills - Tactical Nuke
You can only select 3 killstreaks and you cannot have 2 killstreaks from the same number of kills.
Chat with our AI personalities
The emergency airdrop killstreak is unlocked at 8 kills.
To get the Mario looking emblem of Captain Price you must get a 10 kill streak with no killstreak rewards selected. To clarify: Go into your killstreak reward screen and untick your 3 rewards then back out. Get a 10 Killstreak like this and the emblem is yours.
you can unlock it with you're first killstreak award unlock
kill somebody just before he/she earns an 10 or more killstreak
Kill an enemy just before they earn a 10 or higher killstreak