Oh you're going to make it Mr Musk?

 

Then another feature.

 

Maybe to be able to give it extra thrust from the 'stablize in same place'

with a small control panel. So to move the entire shelf by the

power of the propellers, instead the person becoming the force itself.

 

Of course it would help if the person navigates the library

with use of a say, Ironman-like thrusters from each arms,

and also from the legs. With a backpack for power.

 

But if that is too complicated then, handheld thrusters will do as well.