Ok unless you say that your flat earth is exactly the same as our projection of a round earth, then it would make no difference to flight paths..
YOu do not say that though, you have even presented drawings of what your earth looks like, which is entirely different to the real thing....
Here's another explanaintion of a flat earth.. which further stregthens my point - this is from Sculelos:
"Basically means according to the map me and Jroa posted that the closer you get to the center (The North) the bigger you get in physical size relative to the ground you are standing upon (The South), the farthest reaches of Earth is at Antarctica where the south pole is. If you look at my map above 10 degrees is 5% of 200 degrees.
So for example if I was at 200 degrees I would be 200% bigger then at 100 degrees so the World would appear to be 12,500 miles around instead of 25,000 miles, except that it wouldn't be because if I traveled to the south pole the 200% (maximum) would become 10% (minimum) and the average would be 100% between both of them. So mathematically size all works out if you know that each degree you travel from the North pole your relative size will decrease in relation to your longitude or latitude. Antarctica is the farthest point you can get south in the world but you can never get smaller then 10% without going to the other side. Antarctica is about 10% the size of the Earth in width which say's this is correct. North America would be 172 longitude by 154 degrees latitude which means you would add 74 degrees at an average of 163 degrees which would equal a 163% size boost so 74 degrees would be about 4,625 miles wide which would be pretty correct if you were measuring diagonally. Width should be 154% or about 94.5% of 2/3rds the diagonal which would be about 2884 miles. going from Coast to coast in diagonal direction this is also correct. Finally height should be about 28 degrees or about 1945 miles straight x 186% or about 3617 total miles. However I'm not sure if I'm completely accurate but I'm pretty close. Mapping this to a perfect sphere works very well which is why I think we are in a perfect sphere that is inside of a cube."