Transporting an US army heavy brigade would take upward of 500 c-17 flights... So I shudder to think how many y20 it would take to transport a whole pla armored division. Possibly 2000 ish. Generally speaking, air transport is not meant to be used to move around whole armored brigades but smaller units or airborne brigades, which are smaller and have less and lighter vehicles. And of course, majority of c-17 and y20 missions will be transporting pallets full of supplies and/or key components of specialized units.