In comments, flat earthers again try to claim that a fisheye lens was used to cause the curvature, but none were fish-eye lenses.
My Comment — how we know for sure it’s NOT A FISHEYE: At 20:24, the earth’s surface is near the middle of the lens, where fisheye lenses do NOT bend lines. All of the aircraft’s lines are straight, including the lower-right corner, where a fisheye lens would have radically bent them. Also, the earth’s horizon’s curvature is the same no matter where its placed in the frame. There are many different placements of the horizon in this video.
2:50 The plane flew above above 70,000 feet.
16:00 What it was like when Blair saw the curvature of the Earth.
Video should start at 20:24