**Abstract**

The development of the aviation industry depends on many factors. One of the most important factors is the development of power units. A power plant is a source of energy for an airplane. Without power units, flight is possible, but the transportation efficiency of such flights will be low. So, an in-depth analysis of the power unit structure is an actual task every time. The power unit is composed of several components. Obviously, the main structural element is the engine. However, the overall efficiency of the propulsion unit does not depend only on the engine. Subsystems and subcomponents of power units should have rational performance that can provide high overall efficiency. So, a detailed analysis of each of these structural members is also an actual task. To perform such an analysis, it is necessary to know the characteristics of these components and ways to increase their efficiency. In this chapter, all these features are briefly explained. In addition, some trends for the future development of civil aircraft power units are discussed.

**Keywords:** power unit, engine, aircraft structure, thrust, emission, noise
