You're kind of both right. The virus isn't airborne in the same way that the influenza virus is when you cough or sneeze. Not to be too graphic here but...you gotta be in the same room a someone who is actively projecting the virus...from either end...if you catch my drift...
So if you're in the bathroom with someone who has noro and has the runs and/or is throwing up, then the contaminated liquid can splash or being aerosolized with a flush, and then someone can be infected by actually ingesting the virus particles.
It's not true inhalation, it's actually ingestion, and it's unlikely that you would get an airborne infection from, say, walking through Cabana's while a sick person is in there. But if you walk into a bathroom where someone is throwing up, there's a potential to get sick. And, as always, surfaces are the most likely culprits.