Well...:) those dark beams that project in front of the jets are shadows.

I know it's hard to make sense out of that spacial relationship/equation.

I will make an animated graphic sometime very soon to illustrate how that works. It's about the relationships of the distances involving the jet/trail/"subvisible layer" and the suns position relative to the veiwers location. While it may appear that the beam travels ahead of the plane from a certain point of view...in actuality the beam(shadow) is miles beneath the plane and trail and thus appears to be ahead of the plane(from p.o.v.). It's a matter of perspective.
There is a lot of visual trickery and confusion going on up there. LOTS of changing variables. I will try to make a simple version of this particular phenomenon in an animation and I'll try to illustrate those variables.
Please dont get mad at me.