Nobod has mentioned paint schemes yet.

Did “shark’s teeth” on the nose of, say, P-40s have a psychological effect on their opponents?
Were some German WW1 fighter aces’ aircraft brightly painted to scare the hell out of allied aircrews?
A little more tenuous perhaps but were not photographs of allied bomber crews with the nose art (including bombing tallies) used as propaganda to strike fear into the German population?

Roger Smith.