Thanks for your input, I have flown for several decades.
Great circle (shortest distance between two points on a sphere, where one flies an arc) routes come into effect on distances of 100 to 200 miles, it is very noticeable on greater distances
If the earth was flat, there would be a constant course between any two given points. Flying a constant course on a long leg and one will not get to their destination.
Heh, great example! It will not sink in for the troll, but I consider it very helpful. Flights to Europe from the Eastern Seaboard overfly the waters around Iceland, trips from the west coast to the Orient overfly the waters off Alaska. Obviously they don't do that in order to waste time and money and burn more fuel.