The levitation for scientists using help of a standing sound waves work since the 1970s. Since last century it become one big problem it was not possible to lift the object larger than the length of the used sound wave. But in the end we managed to work around it.
Working together, physicists from the United Kingdom and Brazil managed to last lift and keep the ball in the air from expanded polystyrene, which is 3.6 times greater than the wavelength of the ultrasonic sustained it in the air.
The secret it turned out here to create a standing wave between transducer and emptying system of the object. Even better is that the object is kept in both vertical and horizontal, which means that it does not need to be Additionally, otherwise keep in place not to flew off to the side.
Whether this marks the beginning of the era of flying (with the help of ultrasounds) skateboards and cars? Unfortunately not, because this technology only works with stationary objects. At least for now.