Ok now I am talking from supposition rather than knowledge. And I don't have time to go and google this. But as far as I am aware below a certain altitude (no I don't know what it is) there is an effect (ground, magnetic whatever) that would carry a large metallic object with it. But above a certain altitude (probably inner space), an orbit can be achieved where an object, in this case a helicopter can be independent of the earth's rotation.