Hello friend. Remember That the earth is not completely flat like this ______ but rather is curved up a little bit and so you can this small discrepancy from these heights.
Um... what? Where is the info on this "flat but convex" theory?
Well, I suppose it's an interesting effort to piss off both sides of the debate!
Any curvature less than a full sphere isn't going to reproduce the effects we see at 100,000 feet - you'd have to be a LOT higher than that with a more subtle curve...yet on the other hand, you still wouldn't get sunsets or anything like that without all of the usual FET stuff.
The big problem with a subtly curved Flattish-Earth is gravity.
Real gravity doesn't work on a finite flattish-Earth because there would still be a net force towards the center.
Real gravity doesn't work on an infinite flattish-Earth because it would be like living on a hillside.
Universal Acceleration doesn't work because on the outer edges of the world, you'd keep falling over.
All of the water would run off the top of the world and end up in a large puddle around the perimeter.