Is it possible to reflect light off of air? If so, what would it look like?
Yes. This is how mirages form.
There are some pictures on the Wikipedia page, and if you Google for "mirages" you'll find a lot more.
Mirages are produced by the refraction of light, not reflection.
Kind of. You can put some kind of material in the air, like smoke or dust, that scatters enough light back at you so that it serves as a kind of midair 'screen'. I don't know of any way to do something similar without adding something to the air.
You dont really need particles scattered in the air. atoms themseves can scater or reflect light. Earnst Rutheford showed this with his thin gold foil experiment. Air, of course, is much less dense, but of course there is miles-and-miles of it, depending on the "experiment" so the likeliehood is non-zero.
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