I thought I remembered reading someplace respectable that the apparent curvature of the earth as seen from the surface or planes is actually just perspective, and would look indiscernible on a flat planet (or a huge one). But I don’t have a citation to share. Maybe it’s only true at sea level.
IME the curvature isn't really discernible until far higher altitudes. Most of the "curve of the earth" shots you see are because someone stuck a go-pro on a hiball and a combination of haze and fisheye effect makes the earth look round. If you use a camera without the lens distortion it just looks like a normal horizon.
“Visual daytime observations show that the minimum altitude at which curvature of the horizon can be detected is at or slightly below 35,000 ft, …Photographs purporting to show the curvature of the Earth are always suspect because virtually all camera lenses project an image that suffers from barrel distortion”
Another trick you can do: take this Concorde photo and use the rules of geometry to draw the rest of the circle, and look how small an Earth you’ve drawn.
Think of it this way: imagine you were in the middle of the ocean, just 100 feet above sea level. As you turned your head 180° to survey the horizon, do you think it would look curved?
As I understand it, that was one of the perks of the Concorde in that in flew so high that the passengers could see this as well.