Refraction is a copout.
Call it what you want, it's an explanation and it works. In other words, the bedford experiment
isn't a problem for round earthers. It can be viewed as
possible support for your case, but it isn't necessarily, since it's phenomena can work on a round earth.
everybody is aware of the picture provided. if that was accepted do you think this website would even exist?
No, I do not. And that is the point.
perhaps what you should be doing is explaining WHY the horizon looks flat and not curved at sea level over a (aprox) 5 mile plane.
Because, in short, the earth is huge. It's h-u-g-e.
And, the earth DOES looked curved from planes. I'm not specific about the height.
Where. I live in mexico for many years and see no curve anywhere. Where you see curve
Climb a tall mountain. Ride in a high altitude airplane. You'll see it. It won't be extremely obvious until about 60,000 feet, but you can still see it at much lower altitudes.
Close, but not quite. No mountain on Earth (including Everest) is tall enough to see the alleged curvature, and by all accounts 60,000 feet isn't when it becomes extremely visible, it's when it becomes visible at all.
Sources? I confess that I don't know about mountains, but
you CAN see earth's curve from a plane.
You think i have plane in my back yard to go 60 thousand.

No, I suppose not. But those who do can try it out.
It also provides video evidence of Naboo Starfighters at 60,000 feet.
Multiple, different and photorealistic videos uploaded by private users is hardly the same as identical videos from usually-realistic-but-sometimes-unconvincing movies which took years and many many professionals to make.
I seem to recall my sister bringing home pictures from an airplane flight that she took. I remember looking at them and thinking that the earth looked curved (and this was before I was debating any flat earthers). I might still have them somewhere.