They do but chances are it's not 100% effective.
Rather, "there is no evidence to show that using insecticide to kill mosquitoes inside aircraft cabins is effective in preventing introduction and spread of mosquito-borne diseases."
https://www.epa.gov/mosquitocontrol/aircraft-disinsection
Not sure where the idea came from that spraying the cabin aisle would penetrate the luggage bins, cargo hold, under the seats, or really anywhere.
Rather, "there is no evidence to show that using insecticide to kill mosquitoes inside aircraft cabins is effective in preventing introduction and spread of mosquito-borne diseases."
https://www.epa.gov/mosquitocontrol/aircraft-disinsection
Not sure where the idea came from that spraying the cabin aisle would penetrate the luggage bins, cargo hold, under the seats, or really anywhere.