"Airborne's" a tricky term. There's the ability of the virus to remain intact in dry air, then there's it's stability in fluid droplets such as would be expelled in a cough or sneeze. "Not airborne" would include both to most laymen.
If blood, sputum and saliva are infective when 'attached' to the body, why would they become non-infective when aerosolized by a sneeze, where they can be inhaled directly onto a large mucus membrane surface?
If the virus becomes non-infective when dry, why the extensive spray disinfection of interior and exterior surfaces, sidewalks, vehicles, &c?
It's infective when sitting on a surface but becomes harmless when wafted into the air?
If "not airborne," why mask?