The Short Version
This claim is false. Every major scientific and governmental authority — including the US EPA, Met Office, WMO, and a survey of 76 out of 77 leading atmospheric scientists — has found no evidence of any secret aircraft spraying program for weather control or population manipulation. While legitimate, publicly disclosed geoengineering research (like cloud seeding and stratospheric aerosol injection studies) exists, these are transparent, small-scale activities — not covert operations via commercial aircraft. The "population manipulation" element has zero scientific basis.