Do SAM turrets add streak points?

In modern warfare 3 you can now earn streak points for taking out enemy aircraft. Does the aircraft a SAM turret takes out count for streaks?

No, they do not.

I believe using kill streak weapons like using the predator missile to kill another player, does count towards another kill streak, but I don't think that SAM turret aircraft kills do.

The SAM Turret is used for clearing the skies of enemy killstreaks, it does not add to your pointstreak. Using it does give you XP though and after calling in a certain amount of SAM Turrets you complete the challenge "Keeping Em' Down".