Since the new MacBook Air doesn’t have a fan while the MacBook Pro does, I’m sure there are some differences that Apple isn’t admitting right now. The battery life claimed by Apple is also higher on the Air compared to the Pro. Maybe the Air is throttled or runs at lower clock speeds.
The base model air has 7 GPU cores instead of the 8 that the higher end Air, Pro, and Mini have.
If you configured them the same (chose the more expensive Air), the Air and the 13" Pro have the exact same specs from what I can tell other than a slightly brighter screen (500 nits vs. 400 nits) and slightly bigger battery (58.2 whr vs. 49.9 whr) on the 13" Pro.