Ever wonder what those crazy clouds dancing on the wing are during takeoff or landing.
Well, these are the result of the lift forces which make the plane fly.
Lift comes about because the air pressure is low above the wing, and a drop in air pressure (and temperature) tends to cause invisible water vapor to condense into the visible water droplets we see as clouds.
You can also get vapor trails off wingtips triggered by the same changes in air pressure.
You may also see a small stream of vapor over the wing which may look like jet fuel in some cases but again this will be a concentrated area of pressure change.
These clouds can be formed during any subsonic maneuver that reduces pressure over the upper surface of the wings, like high-g turns.
This video was taken at Birmingham Airport in the United Kindom.
It was taken by flugsug.
You can see more of his work at the above link.
The other vapor effect seen off aircraft is what is called vapor trails or contrails.
Contrail is short for condensation trails and appear as a line of cloud produced by the jet exhaust or can be formed by changes in air pressure from aircraft at cruise altitude.
Despite popular misconceptions, contrails or vapor trails are just that – composed primarily of water, in the form of ice crystals.
Some vapor trails can stay in the atmosphere all day depending upon the temperature and humidity at the altitude the contrails form.
According to Contrail Science, “they are formed when the water in jet exhaust mixes with wet cold air and of condenses and freezes into ice crystals. Contrails are actually a type of cirrus cloud. When the air is wet and cold enough the trails can stay around for a long time, and sometimes spread out.”
This difference between trails that fade away, and trails that spread, is often used as evidence of the “chemtrail” theory, which states that the longer lasting trails (or some of them) are being deliberately manipulated for some reason, which of course is nonsense.
However mostly if they are visible they only last from a