For example, in this video:
I say they either purposely or ignorantly used a frame where the infrared camera has the horizon washed out because a few seconds later in the SAME VIDEO you can see the horizon very distinctly and it's very clearly curved -- and more than that, curved exactly as much as we would expect.
Here is the frame they picked:
But just a few seconds later in the video we can see the horizon much more clearly:
More over, we can see from the dimensions of the aircraft that this is a fairly narrow Field of View, I estimate about 30 degrees here:
In my image the horizon view is about 1330 pixels wide, plugging that and 317,000 feet with 30° FOV into my Horizon calculator we get an estimated 15 pixels for the *apparent* sagitta height. Which matches what we see in the footage.
Flat Earth fails again.