Chem-Trail Nutters Get a Hearing in Arizona.....

[Minimalist]

Or maybe planes are just flying at high altitude?

http://en.wikipedia.org/wiki/Chemtrail_c...acy_theory

Experts on atmospheric phenomena say chemtrails do not exist, and that the characteristics attributed to them are simply features of contrails responding differently in diverse conditions in terms of the sunlight, temperature, horizontal and vertical wind shear, and humidity levels present at the aircraft's altitude.[2][4][7][9][25] In the US, the gridlike nature of the National Airspace System's flight lanes tends to cause crosshatched contrails, and in general it is hard to discern from the ground whether overlapping contrails are at similar altitudes or not.

There's always a guy with a book to sell and some nutty radio "host" looking for ratings from the tin-foil hat club, too.

An article in the Skeptical Inquirer said that the conspiracy theory was first started in the 1990s by "investigative journalists" like William Thomas, and then promoted in the late-night radio shows of Art Bell. The proponents claim that after 1995 contrails had a different chemical composition and lasted a lot longer on the sky; they never acknowledge the photographs of long-lasting contrails dating as far back as World War II.