Sometimes and also depends on the range. Close in takes more than further away. But, by and large, a small degree of tilting back and forth is simply a good rule, but even at close range doesn't take much.

The problem I see is the position of the plane in relation to the sun and mirror. The plane cannot be between the sun and the mirror.

Edit: The sun is behind the mirror. How can the mirror reflect the sun if it is behind the mirror?

Jeanette Isabelle

Welllll, I suppose if the plane was damn close, but in reality, the plan is always so small in relation to the sun that's not generally an issue. Also, it is usually not moving directly at you with the sun behind it, rather it is crossing the sun, but that's really besides the point. I think what some are thinking is the sun, in the illustration, is, I believe, intended to represent the "fireball."

In the lower picture it doesn't appear to me that the shiny surface is actually facing the sun enough to reflect anything.

This is what I was thinking in my edit.

Jeanette Isabelle

I think you all are perhaps over-thinking this. Error is very obvious, not "sneaky" at all. :-)

Oh, wait a minute. The guy is holding the mirror backwards. He has the reflective side facing himself.

Jeanette Isabelle

Nope

How can he reflect the sun that is behind him to a plane in front of him

BOATMAN
John

In pictures 3 and 4, you can see BOTH the plane AND the sun through the sighting hole, looks like he waited until the plane tried to eclipse the sun before signalling.