This video indicates that jet “contrails” over Chattanooga and other cities are injections or deposits of material, not mere water vapor from hot jet engines sucking in cold, damp air at high altitude. The material is coal fly ash, though no doubt some flights emit other materials that contain aluminum and other pollutants. (Geoengineeringwatch.org) (Page 1 photo: Nashville Feb. 20, 2017 Tammy Wallace)