i guess the solution is, from one part, in shaders folder (puff.glsl and included files... )
contrails are made of dark smoke particles (carbon, from burned fuel) and white from ice particles of icing water after burning chimical change from fuel to burned fuel.
the light is specular and prismatic diffraction for the sun. The equation which gives actual contrail might be tuned to enhance the icy reflection (form aside and above) and prismatic diffraction (from aside and below)
the good icing speed, the air temperature and the plane speed, the percentage of water in high atmosphere will be sufficient to make the icing part of contrail beginning at the good visible distance. Sometimes when air is dry enough there is no icy contrail, but just the smoky one (always present)
The smoking part of the contrail is beginning in exhaust part of engine