The sun does not sink below the horizon.
False.
It is plainly visible from a private airplane, when flying westward at sunset, to see the sun dip below the horizon, all one needs to do is to gain elevation a few hundred feet to see the sun re-appear where it went down, and then by descending one can see the sun set again over the horizon.
On a clear day, standing in a valley with mountains to the east, anyone with eyes to see can follow the shadow of the setting sun cast on the mountainside as it moves up the hillside. You can actually watch it move -- but it moves slowly. On an open field, such as Death Valley, you cannot run fast enough to keep up with the shadow it moves so fast.
Of course, some people (generally Modernists) cannot believe what they see with their own eyes.
Seeing the sun when you ascend in a plane has nothing to do with the earth being round. This is explained by the law of perspective, I just referred to.
Wrong again.If it were only perspective, you would not see the sun re-appear when you look at it from a higher elevation, and then set again as you go down. Obviously, you can go up again and see the sun again, and go down again and see it set again. But each time you go up, you have to go up higher, because the sun is moving down below the horizon further each time. News flash: the sun does this south of the tropic of cancer and north of the tropic of capricorn.
Your video above falsifies the view by showing how the sun moves north of the tropic of cancer.
Furthermore, after a few minutes of this, your simple two-seater plane will not be capable of going high enough to see the sun anymore because it has passed beyond the curvature of the earth too far for your plane's ability to ascend. There is an elevation limit on small planes. You would need a pressurized cabin and breathing air supply to go up to say 60,000 feet, where you could then see the sun for another half hour before it sets too far beyond the horizon for you to see it again, even if you were in an SR-71 "Blackbird".
[youtube]https://www.youtube.com/embed/d8I7MLD0YZQ[/youtube]
See what the pilot says at 23:50.
"I've seen the sun rise and set two, three times on a flight..."
At 40:50 they mention the fastest flight, outrunning missles, when the pilot says he saw "some pretty scary mach numbers" he had never seen before. But he cannot say what the speed was, because that was classified information. Hint: greater than mach 3, "faster than a speeding bullet."