The paper presents a control variables’ optimization study for a power production system comprising an airborne module in the form of a buoyant, rotating cylinder, whose rotation in a stream of high-altitude wind induces the Magnus effect-based aerodynamic lift. Through a tether, the airborne module cyclically drives the generator fixed on the ground. The optimization cost function is the average power at the generator during a continuously repeatable operating cycle. The control variables are generator-side rope force and cylinder rotation speed. The optimization is based on a multi-phase problem formulation, where operation is divided into ascending and descending phases, with free boundary conditions and free cycle duration. The presented simulation results show that significant power increase can be achieved by using the obtained optimal control action instead of the initial, empirically based control strategy. A brief analysis is also given to provide a physical interpretation of the optimal control results.