Why are you guys so lazy? If you think it's a good experiment, feel free to conduct it. I was not the one who suggested this experiment and thought it would prove something. I happen to think that it's not a good experiment. It is not my responsibility to conduct your research and do your experiments for you.
Here you go.
https://www.theflatearthsociety.org/forum/index.php?topic=67971.msg1827639#msg1827639I am a bit lazy and figured some RE would eventually do something with the ISS or satellites to determine their altitudes/locations. My patience paid off in this case for the ISS.
I tackled this proposal once on the other forum. I took a look at some projected ISS transits over the United States, looking for one for which I could pick two observers with simultaneous and directly opposite observing locations. I found one on March 6, 2016 that fit the bill: it had a maximum apparent elevation at 5:00:40am Spokane WA time, and 5:59:39am El Paso TX time.
Maximum elevation only 61 seconds apart, that's the best I could do for a simultaneous observation, and those observers in those two locations would have been looking pretty much directly at each other. This is important, because it means the angles of elevation from each location can be used to calculate the elevation above ground of the object being observed.
Spokane and El Paso are 1237 miles apart, according to Google Maps "Distance Measure" tool. (I understand that an FE supporter might challenge that distance as being tainted by RE math, and I'll come back to that.) According to the ISS Astroviewer page (links at the bottom) an observer in Spokane will see the ISS rise to a maximum elevation of 14° above the horizon to the South East, while the El Paso observer will see it at 21° to the North West. Taking for the moment a flat-earth model, we thus have an obtuse triangle with a side and two angles known, we can calculate the rest.
The angle formed at the vertex occupied by the object in the sky is 145°. The Law Of Sines allows us to calculate the line-of-sight distances to the object to each observer. The Spokane leg of the triangle is 772.9 miles, and the El Paso leg is 521.7 miles. From there, we can calculate the height above ground of the object using the Law of Sine again, for each observer's angle. The result is 186.97 miles high. This is far, far higher than any known aircraft has ever flown, or ever could fly.
Possible objections:
1) Maybe the elevations are wrong? I think we can take the projected elevation angles as accurate (instead of going out and observing it ourselves) because if they were not it would be very easy to expose the error, and should have been done by now. Amateur astronomers use these online resources without reporting massive errors, after all.
2) Maybe the distance from Spokane to El Paso is wrong? Perhaps it is, I'll grant you that. Let's say we call it 1 'ground unit' of unknown distance and do the math that way. We end up with the object being at an elevation of 0.15 ground units. Or put another way, Spokane and El Paso are 6.5 times as far apart as the object's elevation. Commercial aircraft typically operate with a ceiling of 42,000 feet, or 8 miles. The aircraft with the highest known operating ceiling ever, the American SR-71 spy plane, could fly as high as 85,000 feet, or 16 miles. Even if my ground unit measurement is less than 1237 miles, it is not off by enough to bring those cities close enough (104 miles) for an SR-71 to appear at 14° from one and 21° from the other.
3) One minute difference in observation time is huge when the object is visible for only four minutes. Seems like it is, yes. However, the object sweeps across the sky in a fairly flat curve, especially as viewed from Spokane. It rises from 10° to 14° and falls back to 10° during the transit. Doing the math again with Spokane's lowest elevation still yields an elevation of 149.46 miles, far too high to be any airplane we know about.
Spokane:
http://iss.astroviewer.net/observation.php?lon=-117.4260466&lat=47.6587802&name=SpokaneEl Paso:
http://iss.astroviewer.net/observation.php?lon=-106.4850217&lat=31.7618778&name=El%20Paso