easiest way for killstreaks is having 5,7,11
5 - predator..can usually get 2 kills with this
7 - harrier strike, while they can get shot down you can easily pick up 2 kills with the bombs then with the hovering pick up a few extra
11 - chopper gunner or ac-130
i will say though after watching that video that seems to be pretty effective and worth trying...also to note he has hardline perk as well