Maybe a fraction less cool, but still amazing in that it essentially displayed an image without any screen or tube, was the “mirror screw” TV receiver employed in Germany during the Reich’s broadcast experiments in the mid-1930s. The viewer saw only modulated flashes of light projected onto a spiral turntable of long, thin mirrors, which spun around many times a second.
Cool as it looks at first blush, I doubt they’ll be able to do anything practical with it. No matter how narrow and/or strong the jets, blowing air is going to produce a shimmering curtain effect. Aerodynamics 101. The only way to stabilize the airflow is to give it a narrow channel to flow through – say, two pieces of plexiglass 1/8" apart. Of course, then you’ve got a solid screen which negates much of the novelty of the display method. You might as well just use a piece of coated transflective glass, then.