I saw a youtube video of a couple sailing across the Atlantic. They used a sextant to shoot the sun at noon and calculate their position. The calculation came within a few miles of what they saw on their cell phone gps. People have been doing this since the invention of the chronometer. Here is how to do it:
https://princetonastronomy.com/2020/05/01/solar-observations-with-a-sextant/Basically, the angle of the sun above the horizon gives your latitude, and the time (related to GMT) gives your longitude. This works on FE or RE the same way, although the numbers in the chart would be different.
I know a man who was in the Air Force and was a flight engineer on MATS cargo flights all over the world. When I told him that someone said "no one knows the distance or where you are over the ocean", he laughed. They flew regularly to the Azores, tiny islands in a very big Atlantic, you really want to get this right, or you have to swim hundreds of miles. The flight engineer was responsible for engine settings and fuel load. He needs this right, or you run out of gas in the Atlantic. He was cross trained as pilot and navigator to some degree.
They had several ways of knowing where they were:
1. Dead reckoning, least accurate, subject to wind error, as Tom Bishop says.
2. Triangulation with known radio stations and a directional antenna. You may have seen military aircraft with a circular antenna sicking out above the fuselage, that is what it is for.
3. Loran, the ground based predecessor of gps. check youtube videos for how it worked.
4. Sextant, as explained above. That is what the plexiglass bubble on top of the fuselage of military aircraft of the 1940s, C-47, B-17, B-24.
He said they always knew where they were, always successfully found their destination, many many times, never ran out of gas. He said the wind had some unknown impact on them, hence the importance of knowing where they were. He also said they knew roughly what the wind would be, needed for fuel load planning. Amazingly to Tom Bishop, all methods gave the same answer to within a few miles. Otherwise, you are in the middle of the Atlantic, short of fuel, and no idea where you are?
If Tom Bishop is right, I am never going to vacation in Hawaii. Does the pilot of an airliner take off for Hawaii knowing he has no idea how far it is, just points the plane in the same direction as last time and it always seems to get there? Amazing, especially with unknown winds that must be hundreds of mph to make the Sydney to Santiago flights work, perhaps in both directions at the same time, or maybe the flights are on different days of the week because they experienced the winds one way on Wed and the other way on Fri? What if the wind blows you off course north and south, seems like the wind would have to blow exactly towards your destination, or north south error.
There is astral navigation, radio navigation, dead reckoning, but per Tom Bishop, the only possible possible technique is "worked last time, cross your fingers". Are the insurance companies aware of this? Of course, it seems to be 100% reliable method, airliners always find Hawaii. Pretty small dot in a very bog ocean, with hundreds of mph winds going unknown directions.
And none of the pilots know, and none of them tell anyone? The pilot and navigator faked it and pretended when they told the flight engineer where they were? They always found the Azores, he never ditched out of fuel.