Generally speaking, you cannot get it from sitting in a room with someone infected. That means it’s not generally transmitted by being in short term proximity. THAT is what airborne transmission means.
You sit across from someone coughing or thrashing about on the floor, tossing tiny liquid into the air...you could get it. But that is “close contact.”
I know it sounds like splitting hairs. But, if it was truly airborne, it would have travelled widely with a lot more deaths.
If you can get it from inhaling particle matter (sneezes etc...) it is airborne IMO.