^^^ An infinite vacuum obviously isn't possible so we're simulating it by leaving the pump running. You said that "if" it was infinite, I'm just stating an experimental setup that allows for it within a finite container.
Since we're pretending gravity is a force I've avoided referencing the aether, if you want concede that the static aether is real then this whole discussion is moot. The 1887 M&M experiment proves the earth is motionless and falsifies the Copernican model; no outer space and no pressurized gas next to a vacuum without a container.
We're not going to get past vacuum pump equals infinite chamber, so let's drop it for now. I'm more interested in the idea that air falls because it displaces aether. I think that you would support that idea, but you haven't stated one way or the other. You previously stated that objects fall in a vacuum because they displace aether. That implies that air would similarly fall in a vacuum unless air molecules are different in some way. Can't that explain how air could be next to a vacuum? After all, we observe that the air pressure drops as the height increases, and the pressure must be close to 0 at the top of the dome over 3000 miles high.
Finally in regards to the force acting on the air molecules, we're not dealing with a solitary particle in an unbounded space. They push on each other and the wall of the chamber and the force pushing is electromagnetism; the molecules are 99.999% "empty space", only fields of force exist and interact.
Air molecules are mostly solitary. Other than gravity/buoyancy, they only interact and encounter forces when they collide with other molecules or the walls of the container. Note that I write "gravity/buoyancy" when I'm referring to the force that causes objects to fall and when being gravity or buoyancy doesn't change anything.
