Oliver Smith, writing in the unlikeliest section of Britain’s Telegraph newspaper (Travel), pooh-poohs the concept of chemtrails and, seemingly not satisfied with rubbishing that conspiracy theory, tries some other aviation-related theories out for size:
The seemingly random appearance of “contrails”, as these lines of condensation are commonly called, is considered by a small but vocal online minority to be evidence of government conspiracy. The clouds are, according to some, in fact “chemtrails” – chemical or biological agents sprayed at high altitude for any number of top secret reasons.
So persistent is the chemtrail theory that US government agencies regularly receive calls from irate citizens demanding an explanation. Pernilla Hagberg, the leader of Sweden’s Green Party, even raised the issue in parliament. The trails which arouse the most suspicion are those that remain visible for a long time, dispersing into cirrus-like cloud formations, or those from multiple aircraft which form a persistent noughts-and-crosses-style grid over a large area.