Technically we do release silver iodine (and other stuff) into clouds for weather modification. So there is some fact in the idea, but passenger aircraft are no

Technically we do release silver iodine (and other stuff) into clouds for weather modification. So there is some fact in the idea, but passenger aircraft are not actively spreading anything. http://en.wikipedia.org/wiki/Cloud_seeding http://en.wikipedia.org/wiki/Cloud_seeding The only reason the US doesn't use weather modification in war is because of signed international treaties.