Not 'much smaller'. Yes MBA is the less-massive one--it's the lighter one--but it's not much smaller than MBP. I wish it were!
In absolute terms, no it's not that much smaller or lighter. But in terms of actual feel they're completely different.
For reference I have a 2016 13" MBP that's bigger and heavier than the M2 Air. I went to the Apple store and played around with the 14" Pro. It felt massive compared to my 13".