Not really... "Thin air" can count for the required "something" if it's, say, moist enough. 2D displays using walls of mist as the projection surface are relatively commonplace already; 3D could theoretically be implemented as well.
How would this work?
For it to be used as a regular 2D display, I could see it. You just need a sheet of mist to project your image onto. But a 3D display would require a VOLUME of mist. So if you have the projector at the front (like a cinema projector), then it will have to project a beam of light through the front part of the image in order to show something at the back. How could this work without creating a visible effect in the mist that the beam travels through?
In any case, I don't think Daniels' gizmo shot a cloud of mist into the room first.
But today's technology can easily produce "freestanding" imagery in empty space by a far simpler means. Just project it directly at the eyes of the audience, by using software that tracks the eyes of each individual spectator and shines the required images directly onto those, customized for each, well, customer.
3D vision is an illusion in any case (even when we're viewing actual physical objects), and the illusion is created by carefully manipulating the imagery falling on our eyes. Doing it eye by eye is merely a minor complication today's computers can easily manage, and probably a lesser complication than those involved in more "conventional" 3D projection techniques.
Got any more about this? It seems interesting.