The engines create smoke .
The streams that jet planes leave in the sky are called contrails. Contrails form when the hot, moist exhaust from the airplane engines mixes with the cold air at high altitudes, causing the water vapor to condense into ice crystals. Contrails can sometimes linger in the sky for a while, creating long white streaks behind the plane.
The contrails are the result of 1200 degree jet exhaust being released into much, much colder ambient air.
The white trail you see behind an airplane in the sky is called a contrail. It's an artificial cloud made by the exhaust of jet aircraft or from the wingtips.
Those lines are created by aircraft flying at high altitudes releasing water vapor in the form of contrails, which are frozen water droplets condensing around particles in the exhaust. These contrails are most commonly seen behind jet engines on airplanes.
Most are limited to 35,000 feet or less, but some specialized jet airplanes have flown above 150,000 feet just short of outer space.
The sky
Give your jet steroids.
well realy no, because its not realy a cloud, it is the smoke coming out of the jet, not a cloud actually a jet stream is a wind current in the upper atmosphere that commercial aircraft use to travle faster. The clooud-like trail behind jets are called contrails and would be considered clouds because it is when the heat causes moisture to gather into small clouds... like how warm breath can fog a mirror.
In the sky, you can see clouds, the sun, the moon, stars, and sometimes airplanes.
A formation
The trail left behind in the sky is actually ice, when the air is so cold its below freezing the vapor turns into ice so quickly that it skips the liquid stage and creates a trail in the sky.
It is condensated air from engines, due to extremely low temperatures at high altitudes the hot jet stream comming out of turbines get transformed in a white cloud. shivering for several mkinutes