What would happen if an infinite plane was below our disk?

Specifically, looking at work by scientists like Forward, lets suppose this infinite plane is made of exotic matter, namely that with negative mass. Of course this is also assuming a level of gravitational shielding or bow shock effect around the surface of terra. Looking at NASA's work concerning the diameteric drive with Forward (in BPPP) or simply by plugging in the appropriate math into Gauss's law we finally have a reasonable source for the acceleration of the Earth in the Cambridge model.

In the past, I thought about replacing Dark Energy with a negative mass as the source that drives the Earth's acceleration, as the negative mass can do so without requiring a tremendous amount of energy; however, I stumbled upon the problem with the acceleration of spherical celestial bodies and the Submoon. What would happen to the Submoon underneath the Earth? Should there be a negative mass as well near each celestial body to achieve parallel acceleration, if DE is not available? If not, how do the celestial bodies achieve such acceleration? Or should we accept Photoelectric Suspension Theory and treat the celestial bodies as metallic discs?

If the other plane is moving the Earth, what is moving the plane?

If I remember correctly, since a negative mass is attracted to a positive mass and said positive mass is repelled from said negative mass, the two masses can accelerate forever without requiring any additional sources of propulsion (if both masses are equally massive).

EDIT: made changes to one of the sentences.