Flat Earthers argue that there is no true Flat Earth map. If this is the case, then how do airplanes and ships know which direction to go to. They seems to know which direction to go to get to certain place and approximately how long it takes. How can this happen if there is no "true map"?

The coordinate system is correct in that you can get to a location by going to a certain coordinate. The coordinate system assumes that the earth is a globe, however, and the coordinate points are mapped onto a sphere. Distances are calculated under this model, and are not directly experienced with any specific onboard tool.

We can't use distances calculated under the assumption of a globe when making a Flat Earth map. We might as well assume that the earth is a globe if we are using a spherical coordinate system. Those distances must be proven.

They know "approximately" how long routes take from past experience, and guess their speed from the theoretical distance traveled.

Per the Southern Hemisphere in the Flat Earth monopole model, the Flat Earth monopole map was not created based on any particular data. It is just a projection of a globe, and has no value in navigation. A true map has yet to be created. The stumbling block is that all listed distances rely upon a Round Earth spherical coordinate system.

Why is relying on a RE spherical co-ordinate system a "stumbling block"?

I'm just trying to imagine how WW2 would have panned out if the Japs had become fed up of trying to guess where Pearl Harbor was, or how tricky it would have been for the USAAF to find mainland Japan in their bombing raids.

US Navy pilots? "Attack the Jap ships at RE co-ordinate x,y. We'll rendezvous at a,b in 50 minutes. Or just turn left at the next wave." I simply cannot imagine how anyone could have operated carriers and planes without very accurate navigation technology, backed up by a paper map in case something technical got damaged.

How many mission records in each category:

- success

- missing in action

- aborted, bad weather

- aborted, tech problem

- aborted, couldn't find it