What are chemtrails and shoud they be a concern?

Question

What are chemtrails and shoud they be a concern?

Answer 1

Some people believe that there is a conspiracy between the U.S. government and the airline companies to spray us with some unknown chemical for some unknown purpose. As the aircraft pass overhead, the trails supposedly contain the mystery chemical.

Answer 2

Chemtrails are a fantasy invented and adopted by bored people lacking of attention and intelligence who desperately need to fill their lives with a sense of purpose. Much like 911 conspiracy media and the supposed moon landing hoax.