—Donna Zubowicz, Lake Havasu City, Arizona The trails in the wake of jets are mostly condensation, caused by the engine emitting hot, humid air into a cold atmosphere. That’s why they are called “contrails,” short for “condensation trails.” Think of this as similar to seeing your breath on a cold winter’s day. But the trails also do contain exhaust, comparable to the way automobiles emit exhaust. Ugh. Yet as far as pollution and climate change are concerned, contrails are considered a minor component.
