They definitely use airplanes. The operator of the airplane that is used in my city use to live right down the street from me. My friend (his next door neighbor) was actually busted like that. Instead of dangling out of a helicopter to go to the site and chop the plants, they send in people to wait for you to come back, if that makes you feel any better. No shit. True story. Nobody said it was easy.
Thats part of the thrill of it I guess. Normally they aren't looking too hard until @ late July or August, ( here at least ), since they are more easily spotted from the air and also because they know you want the fruit and will eventually come back to get it.