uh, and I just read further. It seems to me you, Mr. Bishop, are fixating on the need to prove that distances between points are indeed the distances that people who "believe in a globe" are claiming they are. Your claim that GPS data is based on a globe and therefore cannot be used to prove or disprove groundspeed, distances and other claims made in this thread, is unfortunately not quite correct. Whereas GPS data is indeed based on data derived from the model of a rotational ellipsoid and then corrected for the parts of (round) Earth that don't match the mathematical model with the World Geodatic System 1984 (WGS84), it is not the only way a modern airliner measures it's position and ground speed. As a matter of fact, GPS wouldn't be needed at all (and wasn't as a general rule until the nineties). An Airliner navigates by the use of an inertial reference system, which is self-reliant, if the correct position is inserted before the aircraft starts to move. (By way of design, that reference system would not even work on a flat Earth, especially one that is not rotating.) However, the reference system accumulates errors, and thus the position becomes more inaccurate the longer the aircraft is moving. Old(er) aircraft like the 737-300 generation, 747 classic, DC10 and the likes used solely ground based navigation systems (VOR, DME-DME updating) to correct the "drift" of their inertial reference system (which then was called inertial navigation system). Over oceanic airspace that was not possible, hence there was an increasing drift error the longer the aircraft flew over water (without updating). That was accounted for in the design of the airways, so no aircraft would get too close to another one. Modern airliners update their position also by GPS. So now we have ground based navigaton aids that reflect the actual distances on Earth and that can be used for very accurate ground speed estimation, and GPS, and we find, that there is no difference outside normal tolerances in between the two - neither in position nor in speed measurement. This means, we are using systems that would work on a flat Earth (ground based navigation) and systems that use the round Earth as a model (GPS) and both enable us to navigate very accurately on the real Earth. So, if I read you correctly, this invalidates your claim, that data based on a globe can not be used to prove actual distances on the real Earth (flat or round). Furthermore, any conceivable model of a flat Earth causes distances away from its center to become so large, that far bigger speeds than the actual ones would be necessary to cover them. And by "far bigger" I mean multiples of the speed of sound. However, airliners don't fly that fast. (The problems of supersonic, let alone hypersonic airtravel are rediculously high.) Not even the geatest inaccuracy of an airborne air speed indicator, independent of any navigation system, could explain that impossibility away, because of the sheer velocity that would be required. Air masses don't move that fast either - especially not in one direction and, for the way back, in the other. Which brings me to the problem of weather systems, which cannot be explained by a flat earth eiter, especially one that is not rotating.
Where this may be possible to explain with refering to (for you) more tangible explanations, it seems to be involving a lot of text to write. I would rather like to point out the following:
We, the people who believe the earth is a globe, have a mathematical model of "our" earth. I am working with this model every day, and it works in real life - both, in the air, and on the oceans, to a great precision. Furthermore, weather observation, the physics of gyros, gasses and many, many other easily observabale trades of nature and the world we live in, whatever shape it may have, match that model.
Without disrespect, that the earth should be flat bears a lot of problems. First and foremost, that, as you claim, no model of a flat earth has been charted that can explain and unify all or even a small percentage of the observations that can easily made by man. As a matter of fact, it stops explaining most of the things beyond "the earth does not look like a ball from where I am standing". While you of course have every right to believe anything you like, I hope I am not being rude by saying, that your "model" of a flat earth is very underdeveloped at the moment. So much so, that you (and/or your fellow believers) have to withdraw into the "fog of uncertainty" very often, where suddenly mismatches between your statements and between your statements and so far undisputed claims (e.g. the speed of sound, accuracy of ground speed measurment and so on) are being "explained away" to make other things match - and, as a last resort, the sources of those so far undisputed claims are being brought into disrepute by implying (or openly writing), they are part of a conspiracy. Thus, to a fictive observer without any further knowledge of the earth, who is venturing past "The Earth Looks Flat From My Position", your flat Earth bears more questions than answers, and that is without claiming, that any other model is more correct - wouldn't you agree?
So, for practical purposes, your flat Earth model does not work, starting from the absence of the actual "model", which makes, it seems, - and please correct me if I am wrong - this whole "Flat Earth Debate" obsolete.