About the dillution.
If these "chemical trails" as they call them behind planes are really chemicals, they are >1000 feet in the air and holding position. So where are your chemicals going?
You have to understand how air masses move. A particle (chemical) cant just settle to the bottom the same way it would in water, the atmosphere is infinitely more chaotic and turbulent. The particle has to have enough mass to overcome uplifting forces from the ground heating during the day. This is why crop dusters fly 20 feet over the crops they are spraying. Making a chemical that is concentrated enough to be sprayed from >1000 feet and expecting it to have some effect is pretty absurd. Think about the diffusion/mixing and chemical bonding that would also be occurring, especially over a smoggy city.
And if your going to pose all these bullshit questions trying to frame the government, why dont you probe their motivation? It makes no logical sense. I would believe we were doing chemicals in canada or mexico before I believed that US pilots were spaying chemicals over LA.
Whether its a giant science experiment or not there is no rational reason to believe this. I see planes leaving contrails everyday and still have 10 fingers and two arms. Scientists test chemicals like those in your articles and worse on animals in labs everyday. Why wouldn't the government just do this in lab? You are only asking questions in one direction.
About DoD denial
They still deny the existence of area 51, funding cocaine trafficking, and delta force. Yet how many books do we have claiming the opposite. Secrecy in the business of national defense, don't act surprised.
The government tests things on soldiers all the time (vaccines in desert storm), I do not doubt that the government would test things on its population. But there would be a motivation, not just hey lets spray these people see what happens. This is the 21st century we do real science now.
If the government wanted to poison the people there are much more efficient ways of doing it. (drinking water?) Im not opposed to questioning the government, there is a time and place and this isnt it. You are just picking the wrong topic too defend.
If I need to be more fair in my reasoning, you need to be rational. Our government cant keep its sex scandals quite, how the fuck would they keep this a secret?