Chemtrails

From Wikipedia:

The chemtrail conspiracy theory holds that some contrails are actually chemicals or biological agentsdeliberately sprayed at high altitudes for a purpose undisclosed to the general public. Versions of the chemtrail conspiracy theory circulating on the internet and radio talk shows theorize that the activity is directed by government officials.^[1] As a result, federal agencies have received thousands of complaints from people who have demanded an explanation.The existence of chemtrails has been repeatedly denied by government agencies and scientists around the world

The term chemtrail is derived from "chemical trail" in the similar fashion that contrail is an abbreviation forcondensation trail. It does not refer to common forms of aerial spraying such as crop dusting, cloud seedingor aerial firefighting. The term specifically refers to aerial trails allegedly caused by the systematic high-altitude release of chemical substances not found in ordinary contrails, resulting in the appearance of supposedly uncharacteristic sky tracks. Believers of this theory speculate that the purpose of the chemical release may be for global dimming, population control, weather control, or biowarfare and claim that these trails are causing respiratory illnesses and other health problems.

Chemtrails controlling the weather

Thats Impossible: Weather Warfare on the History Channel

German Military Exposed using chemtrails to control weather

Chemtrails as a bioweapon

Chemtrails over Ukraine before the swine flu outbreak

Chemtrail Documentary