What do you suppose might be the range of this power transmitter? How easily could the range be boosted?

Specifically I am considering the possibility of powering something like those tiny indoor RC helicopters using such an RF field. This could possibly allow them to fly around the room indefinitely without batteries or requiring charging.

What might be the effect on biological organisms from exposure to a field strong enough to power such a product over a radius of ten to fifteen feet or so?

Is it even possible to transmit and recover the required current to power a small motor such as these devices use?