I don’t know if it is my eyesight or not. Maybe it’s my age. But some times, not all the time, when I play a mission, as I approach a plane, I find it very difficult to see the image of the plane, or where to shoot (box). By the time I figure where to shoot, I have been killed.

Can I change the color on the screen, to make the image visible.

Any suggestions? Thanks.
 

You mean you’re unable to see the color of the box? There’s an option to change it in settings, just go the settings > graphics > target color. Move the sliders about till it’s comfortable.
If you mean the planes themselves are small or they blend in then I can’t help...