Thank you for the comment. It sounds right but at the same time to me it still seems more people on the ground shoot at planes than observers looking down on it. But I do not know about these war things.

Artifakts is right, but it also applies if the plane is in flight. If you're in a fighter and want the advantage attacking another plane, you often try to start from a higher altitude so you can dive down on them. If the plane is flying over greenish terrain, it would be harder to spot.

I crop a bit more, but I like to preserve the last helix... to crop more I would cut it...