The article considers the technological and economic application efficiency of the aviation unmanned systems in agrarian business. The most effective types of work for agricultural unmanned aircraft have been identified taking into account the global trend towards the introduction of precision farming technologies. The conversion of manned aircraft into unmanned aerial vehicles is also pointed out in the field of unmanned aviation. It is typical for cargo UAVs. The unmanned version of the AN-2 aircraft is an efficient transport platform for moving goods in rural areas, i.e., in the absence of financially costly infrastructure of modern airfields and airstrips. A mathematical model for the biotechnological system of the technological process in processing crops with aircraft of various carrying capacities is studied. The task of optimizing the aircraft load with chemicals is considered for two technological schemes for organizing their refueling with aviation fuel.