I've been in an airplane on a clear day. I've seen the curvature of the earth with my own eyes, on many occasions. What evidence do the flat earthers have that proves what I saw wasn't real?

One guy in about 200BC, a Greek speaker living in Egypt proved the earth was round and even measured it's size with pretty amazing accuracy.

Why should I believe a bunch of lunatic conspiracy theorists and not all the normal honest scientists who give simple explanations that make sense?

Go ahead, prove the earth is flat. I'll wait :-)