As you look into the sky, you will see what RE'ers call, "some kind of white fluffy things."
These are clouds, and they are your friends, because they will show you the earth is flat.
There are many different kinds of white fluffy things, but the important kind are stratocumulus since their density makes their flat underside easily seen. These are basically white fluffy things with a flat underside.
As these clouds extend into the distance, you have a clear view of their planar nature. The underside is flat, and is parallel to the earths surface. Yet as these clouds extend further and further into the sky, they do not appear, even at the furthest cloud, to wrap around a round earth. They just extend further and further with the exact same planar underside.
I suppose this is where you RE'ers revise your theory to account for "atmospheric distortion" ??