Chemtrail conspiracy theory
A high-flying jet leaving a condensation trail (contrail) According to the chemtrail conspiracy theory, some trails left in the sky by high-flying aircraft are chemical or biological agents deliberately sprayed for sinister purposes undisclosed to the general public. Believers in the theory argue that airplanes don't leave long-lasting contrails under normal conditions, but their arguments have been dismissed by the scientific community: such trails are simply normal water-based contrails (condensation trails) which are routinely left by high-flying aircraft under certain atmospheric conditions. Although proponents have attempted to prove that the claimed chemical spraying does take place, their analyses have been flawed or based on misconception. Overview Multiple persistent contrails Contrails as chemtrails Contrails from propeller-driven aircraft engine exhaust, early 1940s Exhaust gases and emissions False evidence of chemtrails Ballast barrels in a prototype Boeing 747.