People often see the trails of jetplane to be suddenly on and off. Many people use this as example that the trails is a deliberate spraying.
Chemtrail debunker consider this only as a results of sudden atmospheric change. Like mentioned bellow:
The explanation seems reasonable. But still leave a lot of question:
1. Atmosphere is random, but why the trails is perfectly on and perfectly off if it is caused by supposed to be random atmospheric condition?
A natural sky whould produce random level of humidity. If there is no wind, extreme humidity difference should not exist. We should expect to see gradual change to the trails.
But that is not what many people see. Many people see the trails to be very very uniform. The sudden cut is then continue with another very very uniform trails. If trails is created because of humidity, this would never happen.
2. Some people also observe that there are two trails with different place of broken trails. This defeat the theory that trails interrupted because of different humidity at different level of height.
If the sky is completely random at that time then we should see random broken trails every where, but many people don't see this.
If the sky completely homogen at that time then we should see two broken trails happen at the same place, but many people don't see this.
In short, this is not simple. People or even scientist observe effect can not be explained with atmospheric change of humidity.