I never said the shortest route. a plane flying “in a straight line west to east” would show up as as a curve on the map was all I was trying to convey. It’s possible this plane’s bearing doesn’t drastically change throughout this flight. “Straight lines” get real messy when you convert a sphere into a 2d projection for maps.

Then a further addition that there are other reasons to not fly in a direct straight line anyway. “Shortest route direct A to B” is an ideal condition, and the world is an always an ideal place.