Seen some stuff that allows for a room mic, so you get that kind of 'air'. The air you are talking about I guess is probably the type that makes the trousers flap in the breeze in front of a stack. It also applies sound pressure to a microphone, as well as inside the cab. Two Notes and others do model that stuff to some extent, but it is early days.if you're using IR's it's still gonna sound more or less "digital" even with a loaded tube amp. A lot of times what a modeller lacks is a bit of "air" from real cabs and microphones
The interaction or 'air' between the cab and the pups is another. Most common way is to play close to the active monitors to get a bit of feedback. Okay for a home or studio situation, but trickier if on stage with no cab for feedback. Muse guitarist uses modelling and loads etc, but still has one amp he wanders up to on stage when he wants feedback.
I have seen vids of Pete Thorn using a reactive load and IRs and it does not sound digital to my ears. The feel would be different tho. No air.
With the Laney IRT Studio I am getting something I have not had for few years of using only modelling. Not plugged into tube amp that whole time, but with the IRT what I always felt was missing from modelling was suddenly there. I am not sure how to describe it tho. It is just 'something' and I like it