Patrick, this isn't exactly right, there is a small amount of power which is lost in the bearings and in the air friction no ?
The motor is not really at "no load" but "air loaded".
Maybe it's only 0,5 or 1% of the no load power... What's your opinion about aerodynamics and bearings losses ?
(I doubt that a lot power is lost in the bearings anyway, other than that they would be quickly ripped apart...)