Contrails form when hot, moist jet exhaust condenses and freezes into ice crystals upon entering the cold upper atmosphere.

Should you be scared of jet contrails, the white streaks billowing across the sky? John Lin, an associate professor of atmospheric sciences at the University of Utah, sat down with City Weekly to set ...

A: Contrails are what appear to be long lines of clouds high in the sky and they are formed from jet aircraft exhaust, explains Brent McRoberts of Texas A&M University. “Contrails are created when ...