A little googling... yes, that patent really is for aerial dispersal of material, yes the patent is really held by Evergreen Aviation, and yes Evergreen is a known CIA front. Huh. I wonder what the CIA wants to disperse into the atmosphere...
Discussion
It's for fighting bushfires so everything gets fired straight down. Obv it could be used for dumping other chemicals so I could imagine the CIA hitting rival cocaine plantations and possibly important food crops of nations they want to destabilise with a growth retardant of some sort.
I think you're giving them too much credit
You believe the CIA aren't capable of such things?
I think they're capable of all that and much besides. You seem to be trying to come up with a rationale that is compatible with the interests of ordinary Americans (at least through the CIA lens) while I think their use of any tool is likely much more based on naked self-interest and a desire to retain power
You think ordinary Americans are interested in destabilising other nations and allowing the CIA to monopolise cocaine production and distribution?
Nope, but I think the CIA rationalizes that as providing funding for things that are ultimately good and patriotic. Few people are the villain in their own movie.
I suspect that most people are more preoccupied with presenting themselves as good rather than being good or convincing themselves that they are. It's all signalling.