it is possible cf. my post about Terminal floors (levels) and jetways - Yes, I made it ! Without Modular JetBridge
The thing it’s to first draw the pedestrian path, while workers go throw building this object, Go to the upper floor and draws the foundation of your terminal, after this drawing descends at level 0 and clears the pedestrian path previously drawn. Here you are a suspended terminal and Level 0 you can place what you want as objects or material.