Anyone who has worked with ultrasound will tell you it doesn't propagate any distance through air, I know this from designing medical blood flow transducers, I've got practical hands on experience. I wouldn't waste time considering power transmission though air, as for data maybe you could get a few kbits/s. From a coupling point of view, magnetic coupling is probably better and there are some crazy projects out there that claim or aim for coupling over a few meters distance. What the hell is wrong with a Qi charger. I sometimes think that the people developing this sort of shit are really lacking in terms of intelligence just like the the free energy over unity nuts. I could shout PHYSICS 101 but stupid blinkered people would filter that out. Rant over and back to normallity.