[foofighter15]

Going by the poll it is wether or not the plane will take off.
Even if it works, a major safety hazard.
Imagine sitting on the plane enjoying the lovely pre-flight safety instructions. And then all of the sudden you lurch forward because your plane which was getting up to 400 mph was on a treadmill broke, meaning there is solid ground beneath you, and your plane catching traction and takes you right into a brick wall.

So I guess my only question is about the length of said conveyor belt. If the purpose is to shorten the runway, then its plausible, but if its plane lengthed. It wont work