Many theories say that the smoke released from these planes is poison, and others think it is a biological virus. What do you think?
Google has a research project about removing condensation trails, answering the question:
Contrails, short for condensation trails, are the line-shaped clouds that you sometimes see behind airplanes. They form when water vapor in the air condenses around tiny particles of soot and other pollutants emitted by airplane engines.
Google Research
