A description of the state of research on the creation of energy transfer systems for unmanned tethered aircraft is given. A comparative analysis of the options for constructing systems of this class is carried out. The advantages and disadvantages of implementing systems based on direct and alternating currents are shown. Formulas are given for the dependencies of the transmitted power on the structural characteristics of the cable-cable of the energy transmission system. The advantage of using alternating current for the implementation of high power ground-to-board energy transmission systems is substantiated.