here are some people talking about blood tests.
If you're really concerned about toxic materials artificially introduced into the atmosphere, and everyone probably should be, you're barking up the wrong tree.
Try looking at what automobiles, trucks and coal-fired power plants spew into the air. We've gotten a lot better at scrubbing much of the really nasty stuff like smoke, ash, unburned hydrocarbons, carbon monoxide, nitrogen oxides and sulfur dioxide. But you can't remove it all -- and people like their cars and electric appliances too much to just give them all up.
Sure, airplanes also burn petroleum, so they also have emissions. And we're running out of petroleum, so we need to find something else.
But with all the emissions very well known to enter our atmosphere from our imperfect energy technologies, as demanded by our desire for a high standard of living, the notion that this nasty stuff is being secretly and deliberately released into the air by commercial airplanes is just too weird to take seriously.