Something like this has been done before:<p><a href="https://www.thisiscolossal.com/2014/11/an-aerial-laser-display-capable-of-projecting-3d-objects-in-mid-air/" rel="nofollow">https://www.thisiscolossal.com/2014/11/an-aerial-laser-displ...</a><p>Not sure why there don't seem to be any practical uses of it (at least I have not seen any such displays anywhere in my life or for sale anywhere.) Maybe because the brightness of the lasers is a public danger. Seems like otherwise we would have laser video projected onto the sky by now for advertising.