It seems that different models of aircraft may have different aerosol delivery devices, which is why you may see one trail versus two trails. How many trails do you think this one would look as if it was spraying from the ground, if it was at 38,000 feet?http://www.youtube.com/watch?v=q28dQaaLQGQ
Some planes have aerosol delivery devices along the entire trailing edge of the wings I gather.
If you look on YouTube you will find videos of night spraying. I did see that a member of Chemtrails over NZ on Facebook, Mark Baker of Wanganui, NZ, who noticed aerosol spraying became far heavier in his region in December 2011 and is affecting his health stated: ďThey sprayed here late last night
and the day is all white here today. Itís hard to breathe. Iíve had to use my inhaler several times today already,Ē he complained on January 7th, 2012.
According to William J. Gallagher of New Mexico, who spent four years in the US Air Force, it is rare for night spraying to occur, because it is an energy technology and they are taking advantage of the sun's. He said he saw his first chemtrails in the late-1970ís from MacDill Air Force Base in Tampa, Florida and stayed abreast of the militaryís activities. He wrote Devilvision: The World's New Wireless Grid (2008), which addresses chemtrails in Chapter 5.
I don't know how trustworthy his information is, but a lot of what he said during an interview in 2007 made sense. It's posted here:http://chemtrailsnorthnz.wordpress.com/2012/01/28/chemtrails-90-minute-interview-bill-gallagher-the-edge/
That aerosols are sprayed to achieve a lot of energy effects, including environmental control and mind control. We have had a plethora of electronic antenna installed. A lot of the chemtrailing is to propagate energy from sources such as these.