@Nelisme I believe that it's flat, but no one knows for sure. As far as we have measured it's totally flat, excluding hills, mountains, and valleys of course... the Earth is flat.
@TBIman If the earth were flat, the current plane routes wouldn't work. The Earth has been well measured, and it's not only round, it has an off-center bulge just as you would expect from a rotating ball.
@OggggO What are you talking about? The plane takes off and flies to its destination. Then it lands on a stationary runway. Please think before sending me such nonsense next time. Thank you much.
@TBIman Similar worlds doesn't support embedding links. Your willingness or not to copy it is on you. Regardless, the point is that the routes planes take only make sense if they are traveling along a sphere, rather than a flat plane.