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.
A: The jet stream is often described as a fast-moving river of air that forms along the boundaries of the cold and warm air masses that surround the Earth. The greater the temperature contrast, the stronger the jet stream. Low-pressure areas (storms) form along these boundaries and are often near the jet streams. These jets and lows are really waves in our ocean of air and like other waves can interact, amplify and strengthen. Storms don't create the jet stream, but a strong jet stream can help create a very powerful storm.