As in the whole aircraft is flying with the nose lined up with the airstream when you're going fast [ideally]. When you are flying slow, the nose is up more and the prop blades are presented to the air stream at more of an angle.

The prop blades de-pitch right off the bat if the prop isn't stiff enough, then once you reach the point where thrust equals speed you would figure that the prop blades relax to their original pitch.