What If the Earth Suddenly Turned Flat?

Everything on the earth are in the sync with the earth's rotation, but think in this way:
when we jump or throw a ball from a running bus, we come back to the same place or the ball falls on our hand if we throw it straight up. the ball naturally goes up, and naturally comes down with no extra force behaving on it. But, here we are trying to fly slowly above the ground, stay there for few hours, and come back again on the earth. This is not natural, because, by staying there for few hours (or as we like), we are cancelling out the momentum force (even if it exists in this case), and when we come back slowly down we should have shifted to another place. I mean, if we fly up from Asia and stay there for 12 hours, we could reach America without really flying there!! why dont it happen?? this is very confusing and difficult to understand, dont u find this amazing??

It is very observable that flights going from east to west take less time and use less fuel under perfect conditions. When a space shuttle is in orbit the earth continues to move below it. The rotation of the earth holds very little sway on the vessel and its ground speed is astronomical using little or no fuel. The problem with hovering above the ground and waiting for the earth to move below you is that you would have very little frame of reference. We are already spinning with the earth at fantastic speed and as you observed with the bus analogy, an object in motion tends to stay in motion. To leave the earth and "hold still" if we could even make sense of such a notion we would need to cancel out that momentum first, which would take a huge amount of thrust so you would technically be moving against the earths rotation. It can be difficult to conceptualize just how fast the earth is spinning because its is so massive and it all we know.
As per the Seismologist Susan Hough:
If the earth were to suddenly flatten, presumably all sorts of hell would break loose. I guess it would depend on how flat is flat. If we’re talking pancake flat, gravity would be an immediate problem: gravitational attraction goes as G(m1*m2)/r^2, where G is the gravitational constant, m1 & m2 are two masses, and r is distance. A sphere is the 3D shape that maximizes surface area relative to volume, which kind of gives gravity the biggest bang for its buck. If you flatten the sphere, the far side gets closer to the new center point, but the ends spread way out, so surface gravity goes down at the center, and way down at the edges. Lose gravity and bye-bye atmosphere.
Other first-order problems: heat, radioactivity, etc. In our spherical earth, both of these are concentrated in the core. If the earth were flattened, they would have to go somewhere—presumably a lot closer to the surface.