Have you ever looked up at the sky and wondered what those long, white streaks are? Some people believe that they are a type of cloud, but the majority thinks that they are the trails left behind by airplanes overhead.
In fact, both groups are false in their views. No one knows for sure what causes the white streaks. What we do know is that they are not left by airplanes. Airplanes do leave grayish wisps of exhaust in their wakes as they fly, but those are clearly distinguishable from the long white streaks.
It is clear to see the difference. If the white streaks were actually made of smoke or exhaust, they wouldn’t linger in the sky for as much time as they do. In addition, most airplanes do not really leave the streaks of “exhaust” in their wakes.
The theory that makes the most sense is that the white streaks were not left by airplanes at all. They could have been left by other aircraft that travels by night. This way, no one would be able to see the aircraft. In addition, the streaks of white, which can be seen in be early morning, would be there without anyone seeing them being creating.