When I see a plane in the sky, what is the white, cloud-like stream that the plane is emitting?

Question

Something like this: http://www.ap-hydraulics.com/New%20Webpage/skynew.jpg

Answer 1

Are you kidding?  You don't know what a contrail is?  How old are you?

Answer 2

Since most aircraft travel at a cruising altitude of 35,000 ft

moisture from the air goes into the turbine engines heats up and pretty much steams out of the back leaving what they call "contrails"

Answer 3

It's called a contrail or vapor trail.  What it is   is engine exhaust.   Just as a car's exhaust can be seen when the temperature is below freezing, so can an airplane's be seen as they usually fly high enough so that they are in freezing air even in Summer.

Answer 4

It exhaust as in carbon monoxide, carbon dioxide, nitrogen oxides, total hydrocarbons, and individual organic species

Answer 5

Its a contrail.

Answer 6

That would be unburnt fuel, and condensate.  It's really not a great deal different than the exhaust you notice from your car on a cold day.

Answer 7

they are called contrails, basically water vapor condensing from the engines

Answer 8

If it rapidly dissipates, it is a condensation trail.  If it stays there long after the plane is gone, it's a chemtrail.  

http://www.rense.com/politics6/chemdatap...

Answer 9

the exhaust