This enhanced infrared image from NASA’s Terra satellite shows a widespread outbreak of contrails over the southeastern United States during the morning of January 29, 2004. Satellite data are critical for studying the effects of contrails. The crisscrossing white lines are contrails that form from planes flying in different directions at different altitudes. Each contrail spreads and moves with the wind. Contrails often form over large areas during winter and spring. One very popular photo amongst the “chemtrail” theorists is this one from NASA…
via Contrail Science.