Why do commercial airliners sometimes leave a jet stream in the air?
The “jet stream” simply signifies high winds that blow about 35,000 feet above the earth’s surface from west to east. They blow higher and lower according to the season and certain meteorological conditions. Pilots can take advantage of the jet stream to use it as a tailwind to push the aircraft along and save fuel. It also can slow down a plane if the plane flies against, instead of with it. This phenomenon of flying with or against these high speed winds was observed by pilots flying over the Pacific during WWII. Since they are so important in aviation, these high speed winds got the moniker, “jet stream.” The actual visible white stream that you see in the sky behind airliners and other aircraft is steam or water vapor, from the engines. These are often called “contrails”, shortening the words “condensed water trails.” This is a good question. Email me should you like more definition.
