My turn to spew....I understand moisture and combustion and such from engines at various altitudes, but. After reading about this on the paranoid press, I got out my binoculars for closer inspection and noted most times it's from the engines; however. When I am viewing a jet whose engines are attached to the rear fuselage, (not on the wings) and I can plainly see trails from midway on the wings and near the wing tips, what explains that! Also, on those aircraft, nothing from the engines while this was going on?!?!? (Twighlight Zone music please.)
I forgot to mention that a little while later I felt strangely compelled to send all of my money and possessions to the government!