The paper focuses on the main components of the logistics planning process and justifies the connection between the qualitative planning of the required number of units and the availability factor of aircraft. We consider the potential of simulation modeling as applied to the study of the complex systems behavior, and substantiate the application of such modeling in the inventory planning and control system for the operation of state aircraft. It was found that the availability factor, the health coefficient and the cost of purchasing spare parts can serve as efficiency criteria. The increased aircraft availability or serviceability is achieved by minimizing downtime due to the lack of spare parts. In our research we describe the simulation model of inventory stock usage and test the model for aircraft operating as part of an aviation regiment. The simulation model showed almost complete coincidence with the results of an analytical model of a queuing system. This means that when planning material and technical support, on the basis of this simulation model, it is possible to build more complex models for analyzing multi-inventory stocks without applying a complex mathematical apparatus. The model can be used as a tool for planning the required number of units for the operation of state aircraft.