[TomInAustin]

A while back I was questioning freefall experiences and Tom Bishop gave an answer that worked logically if UA was a thing.   2 current threads on UA got me thinking again and I have a new question. but first, some background as I think I know it.

The air is not pushed up by UA but by the ground compressing the air. A plane flies the same way in FE as it does in RE...   Lift created by the wings.   

New question...  if UA does not push the air and the plane flies via lift then why is everything in a plane not weightless? 

We are only stuck to the ground in UA because the ground is pushing up.  In a plane, there would be nothing to push up the floor and therefore we would experience weightlessness.

[Kokorikos]

I can only assume that as the air is being pushed up by the ground so the airplane is being pushed up by the air.

[DuncanDoenitz]

When a train backs into a siding, the locomotive pushes the tender, the tender pushes the freight cars, the freight cars push the caboose.  All experience the same velocity and longitudinal acceleration as the loco. 

The Earth pushes the atmosphere up, which pushes the wings (due to aerodynamic lift), which push the fuselage, which pushes the seat, which pushes your caboose.  Same velocity, same g. 

[TomInAustin]

I can only assume that as the air is being pushed up by the ground so the airplane is being pushed up by the air.

Yup, that makes sense, even though it seems like level flight it's still being pushed up.