Long story short I was messaging someone about flat earth recently and he said ''the plane that can fly the farthest can make trips from Perth to Cape town on one tank. But on the flat earth model the geography is distorted and the result is that the distance no matter which way you slice it is impossible''

I believe in the flat earth, but i had no idea how to respond to this. could anyone help me out with it? I kinda look like an idiot to him right now