Contrail

English is sometimes more descriptive than Japanese. This cloud is just called a "plane cloud" in Japanese and we have no other word for it. Lots of Japanese are misunderstanding that "plane cloud" is smoke emitted from the airplane's engine. I think there are less people in English speaking world who have this kind of misunderstanding because the English word "contrail" or "vapor condensation trail" is explaining what it is by itself. If they know this word, they would know what it is at the same time. There are mainly two ways in which this artificial cloud is created. One is that the exhaust gas, which is hot and full of water vapor, is rapidly cooled and condensed into a cloud. It's just the same as when we exhale white breathe in the cold air. It's interesting that we can tell how many engines the airplane has by counting the trails of the cloud. Another reason for the contrail is also the condensation of the air which is caused by the wings. Vortexes created at the end of the wings cause a difference of air pressure and create clouds. Anyway, we can see contrails more often in Canada because the air is cooler and has more vapor in it. There is no pilot and sailor who likes clouds, but this cloud is the only exception.