Not so, if you use a pair of specialised ultrasonic transducer arrays to move the air instead! (Video, embedded below) Three banks of thrusters provide a 180 degree steerable net force Details are ...

It drives two ultrasonic transducers in parallel, and with them pointing towards each other and a bit of gap adjustment work it can successfully levitate pieces of polystyrene. There was some work ...

The "Ultrasonic Testing Market by Phased Array, Time-of-flight Diffraction, Immersion Testing, Guided Wave Testing, Acoustography, Flaw Detectors, Thickness Gauges, Transducers & Probes ...