The only overpowered ones I can think of are the emergency air drop and the Nuke. The Nuke is overpowered due to the fact that it is, well, you know, a nuke, and the Emergency Air Drop is overpowered due to the fact that you can get an extremely powerful combination of aircaft almost instantly, although I will admit that is quite rare.
Due to the fact that you shoot them down, I would not get rid of them. However, as others have said, you have to switch classes if you want to shoot one down (unless you have a launcher already equipped), and then you will probably want to switch back. Not only that, some launchers only have one rocket and unless you've got scavenger, you have to die to get a second shot, and some of the aircraft deploy flares to confuse the missiles, so all in all, it's quite annoying, but no, not overpowered. The only "dangerous" killstreak rewards (aside from the Nuke) are the AC-130 and the Chopper Gunner, both of which can be easily taken down by simply having one class with either the Javelin or the Stinger and the Cold-Blooded perk.
Due to the fact that you shoot them down, I would not get rid of them. However, as others have said, you have to switch classes if you want to shoot one down (unless you have a launcher already equipped), and then you will probably want to switch back. Not only that, some launchers only have one rocket and unless you've got scavenger, you have to die to get a second shot, and some of the aircraft deploy flares to confuse the missiles, so all in all, it's quite annoying, but no, not overpowered. The only "dangerous" killstreak rewards (aside from the Nuke) are the AC-130 and the Chopper Gunner, both of which can be easily taken down by simply having one class with either the Javelin or the Stinger and the Cold-Blooded perk.