To answer Krautland's question, the aircraft would be hand flown (as has been suggested) but the seemingly accurate hover would be to a large extent be deceptive because of their frame of reference. That's not to say they weren't hovering accurately, but if you were to see the same positional accuracy closer to the ground it may look less impressive!
A comparison would be if you've ever seen a military fast-jet display team : from the ground the poistion keeping looks rock solid, but from the cockpit there is a lot more apparent movement.
Similarly, if you are flying at 3000 ft and maintain your height within +/- 20 ft that seems pretty good, but if you are flying down the beach at 10 feet, that accuracy would be less satisfactory!
On the other hand, you would actually be able to maintain the 10 ft at about +/- 1 ft
