contrails are "clouds" formed by the hot, humid air from plane/jet engines which mixes with water vapor high in the sky, then turning into ice crystals which then create contrails.
Contrails is a shortening of condensation trails.
No it is the weather that facilitates the production of contrails.
Jet contrails are water condensation resulting from the rapid compression and decompression of the air around the wing as the airplane moves through the atmosphere. The atmospheric conditions have to be just right for contrails to occur, and that is why you sometimes see contrails seem to wink off and on, as the airplane passes through drier air the contrails will stop.
To be an airplane with jet engines? All jet airplanes leave contrails.
Contrails
Any kind of powered airplane can leave contrails under the proper condition. Rocket planes always leave contrails. Jets usually leave contrails but may not if the atmospheric conditions are not right. Even internal combustion engine planes can leave contrails if they operate at very high altitude and the atmospheric conditions are just right. For more information, check out this link. http://cimss.ssec.wisc.edu/wxwise/class/contrail.html
water vapor
Contrails
No. Contrails are long, narrow, thin clouds left by aircraft at high altitude. Cumulonimbus clouds are enormous, thick, towering storm clouds.
Contrails or condensation trails
Spacing Out - 2012 Circular Contrails Caused by UFOs 1-42 was released on: USA: 22 March 2013
Contrails are long, artificial clouds that are man-made, sometimes trailing an aircraft. They are made most commonly by the water vapor in the exhaust of the engines of aircrafts. However, they can also be made from changes in the air pressure.