Rule 5b. Never use single quotation marks in sentences like the previous three. Incorrect: I had a visit from my 'friend' the tax man. The single quotation marks in the above sentence are intended to send a message to the reader that friend is being used in a special way: in this case, sarcastically. Avoid this invalid usage.
Why do jets leave a white trail in the sky? Jets leave white trails, or contrails, in their wakes for the same reason you can sometimes see your breath. The hot, humid exhaust from jet engines mixes with the atmosphere, which at high altitude is of much lower vapor pressure and temperature than the exhaust gas.
In what atmospheric layers do planes and jets fly? Smaller aircraft fly in the troposphere, the lower level of the atmosphere. Military and passenger jeys fly into the stratosphere (above 8 km or above 26,000 feet) to reduce tâ¦he air friction they encounter, and sometimes use the jet stream to improve their speed.