Very good observation about the distances being greater at altitude. If you drew a line 30,000 feet up in the air at your takeoff and landing points you technically cover a little bit more distance than if you were at sea-level the whole time.
Is that maybe why when they fly from LON to NY say, and take aboard an atomic clock and then say, that they have gained or lost x minutes of time, and then start to assume that in travelling from A to B one`s body/time/zone. . . /thing slows down or speeds up. . ?
Its funny how they never calc the angle at altitude thus increasing the ground distance (experiemnt) take two small knitting needles, one large orange, place the knitting needles in the orange like a pair of alien type antennae splaying apart from the centre at approx 20 degrees offcentre (you might be better using the sine from the suraface of the Earth, or not . .) - voila! dist between needles at the suraface of the orange is x and the dist between the two needles at altitude above the orange (i.e., at the ends of the needles) is greater.
So. . . .to go from a to b at altitude will take longer even though the distance is 2geographically the same but it is not the same from a Spherical Geometric point of view. ( I bull---t) Except that the distance at altititude is further than at the surface, this is NOT bull---t and all the navigation caluclations are based on measuremnt on the surface.
That is why they think your time/clock alters when you travel and that time slows down or speeds up. . . ah well, these are probably the same people that believe in the displacement theory.
Sorry, I, I just had to share that with you guys, its Jane, she has inspired me to be a scientist - I think she is building either a new ICBM or alternately a new space craft which needs little fuel.