português
contrail 
An artificial cloud made by the exhaust of jet aircraft or wingtip vortices that precipitate a stream of tiny ice crystals in moist, frigid upper air.
1
A condensation trail arced suddenly into the sky, launched from one of the Iscan heavies.
2
Condensation trails are a consequence of interaction between the exhaust gases from a plane's engines and the surrounding air.
3
But in fact he was curious about condensation trails, those elongated streaks of cloud that form a wake behind high flying aircraft.