Contrails vs Chemtrails

Difference in-between contrails and chemtrails? Contrails disappear very fast (if visible at all), the later not - they spread and linger. Dave Planes @plumber22: “Good video, shows 2 planes crossing paths one producing contrails the other not. One above 30000ft the other below. The higher the altitude the colder it gets. No different from a car exhaust on a winters day.“ Source: