There is unfortunately a growing cabal of these chemtrail nutters operating in Melbourne. They post regularly on Youtube and their biggest target is the QF63/64 which is always at cruising altitude overhead Melbourne, and hence more prone to emitting a contrail there.
Recently they visited Sydney Airport with a plan to "confront" the captain of the QF64. Fortunately the crew was tipped off and ushered through a back door by Customs.
The defining characteristic of these gentlemen is the unbending belief they have in their cause and a steadfast refusal to listen to any counter-argument... try it and they will simply block you from their Youtube Channel. Their other defining characteristic is a staunch anti-science bent. Don't even try explaining Occams razor to them. One of the worst Peekay22, recently filmed an AIr NZ 767 on its way to Perth and absolutely at a loss to explain the dark line visible in the sky (it was the shadow of the contrail) with out reference to "guidance beams for the attack."
Ordinarily I would advocate simply ignoring them but they appear to be on some sort of direct action trajectory. Some already advocate shooting down offending aircraft. Whilst QF is their main target they have posted recently on "Attacks" by AirNZ and Emirates aircraft. I believe the AFP have been informed about them and while the threats come from likeminded souls apparently overseas, one wonders how long it will take them to take the next step.