Well, in CoD4 killstreak rewards end with a helicopter after 7 kills. The highest scored by a person ever, I do not know. It is hard to tell as many players glitch, hack or cheat the game and therefore you cannot use their numbers as a basis for information. My highest killstreak is 27, and it stopped there because the game ended. I was 27-0 with the potential to keep going, so it is tough to say what the highest killstreaks are. But there are people with 40-50 killstreaks.
NUKE!!!
The best killstreak is the Tactical Nuke but use killstreaks that you can get frequently.
Get 47 killstreak on call of duty modern warfare three
The emergency airdrop killstreak is unlocked at 8 kills.
Kill 10 enemies with a single killstreak reward
you can unlock it with you're first killstreak award unlock
by killing someone with a ten or more killstreak that's for the emblem
You can't. That is the only killstreak you can't get from a care package.
Kill an enemy just before they earn a 10 or higher killstreak
The answer to that would be no. If you have a killlstreak when a game ends, the next match your killsreak will strat over. However, your killstreak will be recorded in the barracks and under the leaderboards.
by equiping the killstreak and getting 25 kills (24 if you use hardline) without dying
To get UAV on multiplayer, you must get a 3-killstreak and press right on the directional pad.