I think you can probably tell them apart (political claim type versus kill the lot type) so that may impact my decision, but I am firmly of the 'take them out as soon as you can, if you can' camp (exceptions would be if they were wearing explosive vests with dead man triggers, holding a grenade with pin removed, etc.).

I think the population, as a whole, is more inclined to cooperate to defeat hostages on a plane in a post 9-11 world, as the loss of life on board would almost certainly be less than the loss of life on the ground if that was the intent of the terrorists. Even if the terrorists had small arms (I am assuming the likelihood of anything larger than a handgun is remote) there is a finite number of shots they can fire before needing to stop to reload.

I also think pilots are maybe more likely to cause potential harm to passengers to save the plane load these days as well (e.g. knocking out oxygen supply to the cabin) which would be a good option, provided no dead man triggers of course!