The problem with you diagram is that real contrails rarely persist for more than about 15 or 20 minutes (on very rare occasions they may persist longer but the emphasis is on RARE). Generally you watch a plane producing a contrail and following it back with your eye that only a few miles back it is already breaking up and disappearing.
The key differences on Chemtrails are persistence (they linger and spread but do not dissipate as do normal contrails), and the altitude at which they are formed. Contrails, real ones, only form at high altitude and Chemtrails can be seen to form at altitudes well below where contrails form.