Chemtrails: Still Haven't Blown Away

by Brian Dunning
May 5, 2026

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“Spray ops today, keep your kids inside,” said a message posted to a Facebook group for people in my town. Accompanying it was a photo of the beautiful clear blue sky, striped with three airline contrails, thin white lines way up in the stratosphere. “Spray ops,” they called it. This was, of course, a person who believes the “chemtrails” conspiracy theory: the idea that airlines worldwide, perhaps working with other military or commercial aircraft fleets, have been engaged in a decades-long campaign to spray toxic chemicals of some kind over populated areas. Secretly equipped with spray nozzles and loaded with massive tanks carrying tens of thousands of gallons of chemicals, these aircraft and their operators have refueled and reloaded their tanks in plain view at airports worldwide since the 1990s at least. Some believers say the chemicals are drugs intended to keep the population docile. Some believe it is a mass vaccination program. Some believe it is a vaguely defined program to control weather so that violent storms or earthquakes can be used as weapons of war. And as more attention has shifted toward climate change mitigation, some believe it is a geoengineering project to combat warming. But no matter what version of it you believe, the entire concept is perhaps the most wildly implausible of all conspiracy theories.

I first did a Skeptoid episode on chemtrails back in February 2007. I have a 2007 Jeep, and it’s got rust on it, is beat up all over, and has gone through two suspensions — that’s how old the chemtrails episode is. It was episode #27; this is episode #1,039. It came out over a thousand weeks ago; that’s nineteen and a half years. Here is a brief snippet from it:

I read a fair amount of skeptical, paranormal, and conspiracy websites, but I don't recall ever reading so much vituperation, anger, and name calling as when I read a few forums discussing chemtrails. If you're not familiar with the term, chemtrails are what some conspiracy theorists call aircraft condensation trails. Most of them don't believe that conventional contrails exist, and that when you see one, you're actually seeing a trail of mysterious airborne chemicals sprayed from the aircraft. Those who do concede the existence of contrails often claim subtle differences in appearance or behavior between a condensation trail and a chemical trail.

At the time, I figured a strange belief like this could never last very long. It would have been so trivial to prove that even a single plane was equipped to do this, and yet that has still never happened: not a single spray nozzle or gigantic tank has ever been found on a plane that’s not a crop duster. And the claim usually involves big commercial jets, often regular airliners, doing double duty flying passengers and spraying whatever evil chemicals one chooses to believe. In decades, not a single Airbus or Boeing employee, airport mechanic, luggage worker, food service employee, or other tarmac worker has ever broken silence to break what would be perhaps the news story of the century. The most rational explanation for this is simply that no such personnel have ever encountered such equipment.

A major 2016 study presented shocking findings: Fully 10% of Americans believed it was “completely true” that tens of thousands of commercial airliners a day are deliberately spraying some kind of mixture of toxic chemicals, and a further 20-30% considered it “somewhat true.” That is an incredible percentage of otherwise intelligent, functional adults to believe something that is completely false, and even trivial to disprove.

And this was only in 2016, long before full-spectrum conspiracy theorist and anti-science zealot Robert F. Kennedy, Jr. was made Secretary of Health and Human Services. Since then, belief has skyrocketed in the United States. Kennedy has been a firehose of misinformation on the topic. He has said chemtrails are being sprayed by “Department of Defense or the intelligence agencies” and that workers in the program sign confidentiality agreements which send them to jail for 20 years if they ever say anything. He has said the US is “weaponizing” chemtrails to “attack other countries.” He famously retweeted a social media post about chemtrails, adding “We are going to stop this crime.” He also tweeted that laws are needed to ban chemtrails to stop “dousing our citizens, our waterways and landscape with toxins.” He has also said DARPA is the one responsible for chemtrails, which “come out of the jet fuel,” and warned that he’s going to find those responsible and hold them accountable. When the UK announced it planned to research the potential for atmospheric aerosols to combat climate change, Kennedy tweeted “We will soon end this crime against humanity and our planet, and bring justice to the plutocrats who are perpetrating this mass uncontrolled experiment.” He also joined the chorus of crackpots who blamed nefarious chemtrails for the 2024 floods in Dubai, a claim long thoroughly debunked by meteorologists.

Driven largely by Kennedy’s very public ignorance and paranoia, some 30 US states have since proposed or advanced legislation to ban the practice of spraying chemtrails! It’s like outlawing leprechauns or ghosts, and campaigning passionately to get it passed.

This has even reached the federal level. Sponsored by Marjorie Taylor Greene while she was still in Congress — someone renowned for having no bar higher than TikTok for whatever she chooses to believe — HR 4403, the “Clear Skies Act,” bans and imposes harsh criminal penalties for all intentional atmospheric alteration. The bill emphasizes “weather modification,” confirming that Greene understands neither climate nor chemtrails; yet so far as I could tell, it would also ban the operation of any internal combustion engine. Perhaps this is why her bill remains languishing in committee.

All of the relatively new attention toward climate change mitigation has definitely made the chemtrail conspiracy theory both murkier and more blurry. As more of the world has shifted focus toward climate change mitigation, any number of climate researchers have performed small-scale experiments. It’s called Stratospheric Aerosol Injection, and the basic idea of the current leading proposal is to mimic the atmospheric effects of a natural volcanic eruption, something that has proven cooling effects. The cost would be something like $18 billion annually per degree of warming avoided, which is a drop in the bucket compared to the costs worldwide of mitigating climate change effects such as sea level rise and planetary freshwater redistribution. So the idea is not without merit, and thus study continues. Unfortunately, this gives chemtrail conspiracy theorists something they can point to as a precedent confirming their conviction. It’s not, but some of them claim it anyway.

But for chemtrailers to cite legitimate geoengineering experiments as proof that they were right all along is just sanewashing what they’ve actually been claiming. Geoengineering experimentation has been on a tiny scale, and usually involves balloons because they go much higher than aircraft. Yet the chemtrailers claim many decades of countless daily flights worldwide, all done in secret but using regular commercial airline flights, and that whistleblowers have been routinely silenced or killed. And while these days they may sanewash their claims by citing geoengineering as the purpose, historically it’s been that the government is spraying poisonous chemicals to pacify or dumb down the population to keep us all compliant. Kennedy himself has conflated chemtrails and geoengineering and even cloud seeing by farmers so much that there is really no difference anymore in the chemtrailer community.

But regardless of the purpose, the altitude at which chemtrails are laid by aircraft — typically between 30,000 and 42,000 feet in the lower stratosphere — is not an altitude that’s useful for a single one of the speculated purposes. To wit:

• If the idea is to drug the population for any reason (forced vaccination, mind-altering drugs, sedatives, etc.), planes high enough to leave contrails are far too high. It would be necessary to deliver a pharmacologically significant dose, but release from such extreme altitudes would have the following problems:
  
  
  • Massive dilution. The materials would disperse across enormous volumes of atmosphere, where they’d be subject to wind shear, turbulence, and convective processes to scatter it everywhere. It would take hours or days to reach the ground, during which it would travel tens or hundreds of miles and be impossible to target.
    
    
  • Exposure for that long in the atmosphere would cause the chemical agent to break down from UV radiation, temperature extremes, and atmospheric chemistry.
    
    
  • Due to the extreme dilution and dispersion, what might eventually reach the ground would be at parts-per-trillion levels or even lower, which is orders of magnitude lower than any pharmacologically active substance. The only way to overcome this would be by dropping impossibly large quantities (thousands of times greater than what’s observed, or more), which is far more than aircraft could ever carry.
    
    
• If the idea is instead to perform Stratospheric Aerosol Injection for effective geoengineering, then airliner altitudes are too low. SAI programs would only be efficient between 50,000 and 82,000 feet, far above the ceilings of even the most capable airliners.
  
  
  • These higher altitudes are above the weather, so particles would be unaffected by rain, convection, and turbulence. It’s a stable zone, so particles remain there for 1-2 years. In fact, it’s so stable that there is a naturally-occurring aerosol layer of sulfates there called the Junge layer. It still contains particles from the 1991 eruption of Mt. Pinatubo, 35 years ago as of this writing.
    
    
  • This region also has Brewer-Dobson circulation, a global atmospheric current that redistributes material here laterally evenly around the globe, but not up or down. This means you can dump larger loads here in just one place and have them go where you want them, which is far more efficient than having to distribute them yourself.

So if some malevolent entity is indeed engaged in a decades-long, protracted campaign to spray something into the atmosphere for some evil purpose, they’re doing it in the most wasteful and least effective way possible. Considering how much it would cost them to retrofit tens of thousands of aircraft so massively, and pay off all the mechanics and engineers involved for their silence, plus all the ground crews and air crews and the countless other parties involved, you’d think they could have afforded to pay a single atmospheric physicist for a single afternoon of his consulting time.

Every day, countless tradespeople use sensitive instruments to chemically analyze the air around us. These include HVAC technicians analyzing for leaked refrigerants; environmental health inspectors using electrochemical sensors to find volatile organics, fire inspectors determining a building’s safety for reoccupation, pest control experts with gas chromatographs looking for residual fumigation gases, vintners with UV fluorescence detectors check the fermentation of their wine, art conservators with ion chromatography systems checking for off-gassing from conservation chemicals, cannabis cultivators with infrared analyzers checking CO2 enrichment levels, semiconductor technicians with mass spectrometers looking for any kind of contaminants, food processing inspectors with gas chromatographs looking for chemical sterilization residues, even museum climate control techs looking for anything and everything that might possibly impact their artifacts.

Not one of these professionals has ever reported detecting the presence of mind-altering drugs, aerial vaccines, or climate-fighting sulfate aerosols.

So I don’t want to be a radical here, and suggest a fanatical alternative, but I feel I must point out one possibility: that exactly as much nefarious atmospheric activity is happening as is indicated by the evidence, which is none; and that the airline contrails we see are exactly what we expect when water vapor from hydrocarbon fuel combustion encounters the extremely cold air at high altitudes, rapidly condenses and freezes around particulates in the exhaust stream, and forms visible ice crystals that create the contrail.

But that’s just me being a revolutionary.

By Brian Dunning
Follow @BrianDunning