Not in my experience. Usually the only thing I ever see in the air are jets dropping napalm, and AA doesn't help with that. I run SAM as one of my killstreaks because it can sit and take down spy planes for half the round without me having to worry about it. If someone tries to launch anything in the air, it goes down before it's a threat. Including care packages. You can't defend the air with a rocket launcher nearly as well as I can with a SAM.
I always appreciate a guy on the team willing to run SAM turrets. Same with guys who spam spy planes instead of RC-XD. For most of my classes, I run Strela-3 not because of spy planes or CPs, but just in case I spot a chopper gunner or hind. I get so much joy out of downing those things before they can get any kills.
I've been playing a lot of Demolition (for the first time) because I wanted to unlock Ghost and Ninja pro. Anyway, it's extremely frustrating. If you happen to be on a winning team then it's great. And if you are on a losing team, it's terrible. I know that sounds obvious but from what I've seen, the margins are more pronounced, more often, in Demolition than say TDM or Domination.
Also, what's worst is I can't help but feeling that most of the time my teammates are playing TDM instead of an objective game. For example, we are defending and A is already blown up. B is armed and I see green dots going the OPPOSITE direction of the bomb. Most games I feel like the only one rushing the bomb and trying to plant or defuse it. I will say that usually some person in first place on my side will have like some crazy kill ratio like 2:1 or 3:1. I guess they are helping in that regard but deaths all over the map don't really seem that helpful to me. I'd like some guy watching my back as I am working on the target. Usually I'm the only one there.
These people didn't click on Demolition by accident. If they wanted to just do a killfest, why not do Free For All or TDM? Am I overreacting?
You're seeing some insane scores in Demolition because people are generally only in 1 of 4 spots. Their respective spawns or the bomb sites. There's no maximum kill counter and games can last pretty long which leads to epic kill counts from guys who know how to use Napalm Strikes or B52s. Once you complete Ninja Pro or any other perk that requires planting/defusing, demolition becomes fun as hell, given you aren't anal about mission objectives.