Choppers used to be used in the boll weevil program to spray in the tight spots the planes couldn't get to on the edges, but were too far out for the mist trucks blowers to reach. Dang they were expensive though!!
They were also used around Memphis where there is cotton around populated areas out by the Ag Center within the city limits, since they are much more precise in their application for those situations. People still complained about health problems from "that stuff they were spraying" because they happended to drive by during the application.....

Malathion doesn't cause respiratory problems that people were complaining of - it is the same thing the mosquito man uses in your neighborhoods (when they do send the mosquito man out - they only send him out here if there is a complaint of increased activity).