What method were the goblins going to use in Jordon? They had predicted 85,000 deaths IIRC. It was something on the top of skyscrapers. I don't know the mechanics of their plan.
The only efficient way I can come up with is a low altitude sprayer similar to crop dusting. The helicopter couldn't be a tourist thing, it'd hafta be their own.
B/C doesn't fit here.
A helicopter can't do the damage to a building that a jet can do. Different issues entirely.
I hate to say this, but the only effective use for a stolen helicopter would be around 1850'.
Ah! I remember you saying that was the altitude the Hiroshima bomb detonated, right?