The night sky seen from the northern and southern hemispheres is radially different. No matter how powerful your telescope you can not see stars that are on the other side of the planet from your position. That is what we observe and it makes perfect sense for a ball earth. But why would it be true for a flat earth?
Despite the height of an object above our heads, it will eventually be obscured by objects arising from the flat earth plane.
I have no idea what you are trying to say.
Okay, let me elucidate.
A plane is flying from N to S.
You do not see it immediately due to clouds between you and the plane, but can hear it.
Then, it appears to you from between the clouds, then disappears again briefly, but reappears.
As it makes its way further S, it disappears behind a ten foot tall tree immediately behind you, then reappears briefly, only to disappear behind a water tower 1/2 mile away from you.
Then it finally disappears from your sight behind a distant line of low level clouds 10 miles down range of your position.
In the far north or far south the stars are completely different. How can you explain that for a flat earth?
That has nothing to do with the shape of the earth.
I would expect to see different things over my head as I move about, even in a 10x12 room.