I have 3 brothers, all pilots.........they are "Flat Earthers"......... you see curvature in commercial jets because of the structure of the windows I used to have a bet posted, for years........ "If anyone can give me co-ordinates that are between 2 pieces of land, separated by water, that are a minimum of 100 miles apart, where curvature consistent with a 25,000 mile circumference "globe"........you put up $1,000,000 against my $1,000,000 ...I will pay to have a crew do measurements. I stopped posting the bet, because the amount of money a crew was asking got ridiculous.......but no one ever took me up on the bet, even though --- it should have been a free million dollars