During Johnson’s presidency, the U. S. did in fact pursue known weather modification programs. One was Project Stormfury, a federal effort aimed at weakening hurricanes by flying aircraft into storm systems and seeding clouds with silver iodide in an attempt to disrupt storm structure. Johnson even referenced efforts involving a hurricane near Florida in a letter included among the documents. Another program, Project Popeye, became one of the most controversial weather modification efforts in U. S. history.

Beginning in 1967 during the Vietnam War, the U. S. military conducted cloud-seeding operations intended to extend monsoon conditions over enemy supply routes, particularly along the Ho Chi Minh Trail. The objective was to increase rainfall, create mudslides, and disrupt troop and supply movements. That operation is historically documented. But online speculation has gone much further.

Some conspiracy theorists have pointed to the declassified files as supposed proof of a decades-long secret “chemtrail” operation involving mass poisoning, climate manipulation, and atmospheric spraying over civilian populations. Claims circulating online allege jets are dispersing dangerous chemicals including aluminum, barium, mercury, graphene, and other compounds. One social media post claimed, “Those long-lasting trails that turn blue skies into milky haze for hours? Not condensation. That’s poison falling on your family, your water, your lungs.” Health Secretary Robert F. Kennedy Jr. has also made public comments suggesting concern about chemtrail claims.

“Those materials are put in jet fuel,” Kennedy said in April 2025. “I’m going to do everything in my power to stop it. Find out who’s doing it and holding them accountable.” However, mainstream scientific consensus does not support chemtrail claims. Scientists overwhelmingly say the white streaks commonly seen behind aircraft are condensation trails, or contrails, created when water vapor from jet exhaust freezes into ice crystals at high altitudes. That phenomenon has been well understood for decades.