I don't know what they are, but I've been plane-spotting all my life, and they've only been doing this for the past 15 years or so. I would like to know what they're spraying in such large quantities and why. You don't want to konw? Are we not allowed to point out obvious things like planes spewing massive plumes of God-knows-what? I may be a "nut" in the mind of someone who is clearly not to bright, but I am inclined to wonder about strange new things that are being done RIGHT IN FRONT OF MY FACE WITH ZERO EXPLANATION.