So therefore we can disprove the constantly accelerating disk earth with . . . aeroplanes!!!

If the earth is constantly accelerating, then every plane that took off would come crashing down to earth as soon as it stopped accelerating and hit cruising speed.

Sorry. As far as I can see, the only difference between the "accelerating pancake"-theory and the "gravitational planet pull"-theory is that the actual g experienced by the airplane at cruising altitude would be a tiny bit less than the actual g experienced on ground. Except for that, both theories are compatible with airplanes flying. The thing that keeps the plane from falling down is aerodynamic lift.

Though, what I do wonder about in the accelerating pancake theory is ... what is keeping the air in place? It should spill over the edges and fall of the pancake as the pancake is accelerating.