When you look outside of the window of a plane, if you are high enough, you can see the curvature of the Earth. Having seen this first hand, I think it justifies the roundness of the Earth without relying on third-party info.
There is no curvature, so don't know what exactly did you saw.
Can you provide us proof or evidence that can back up your claim?
Like this:
Commercial Airliner USA LAX to Frankfurt Germany 5,800 mile trip NO CURVATURE https://www.youtube.com/watch?v=jB5YwfUcdWI
LAX to PHX Where is the Curvaturehttps://www.youtube.com/watch?v=3Nbg00TJqJo
There is also footage from concorde, no curvature, high altitude balloons, no curvature. Actually tons of them, all without curvature.
There are a reasonable number of videos and stills that show the curvature of the earth from high altitude. Many are listed right in this thread. Why do you want a repeat?
This reminds me of my second post to this thread:
1. Launch a balloon with your own camera attached to it:
https://www.youtube.com/watch?v=UAifzh7_-cg
2. Sail around the world on your own.
3. Become an astronaut.
https://www.youtube.com/watch?v=UAifzh7_-cg
2. Sail around the world on your own.
3. Become an astronaut.
...but the curve is going the wrong way in that video!
The options were flat or spherical, now you've gone and complicated things by offering evidence for a concave earth.