In recent years, drones have witnessed rapid development in propulsion technologies, with a clear shift toward the use of electric motors compared to traditional internal combustion engines. This transition is attributed to a set of engineering and practical factors that have directly affected the performance and efficiency of drones across various applications. Electric motors operate by converting stored electrical energy in batteries into direct mechanical motion through magnetic fields. This gives them high energy efficiency, reaching in some cases between 85% and 95%. They are also characterized by their lightweight design, ease of operation, immediate response to control commands, and lower maintenance requirements compared to conventional systems. In contrast, traditional engines rely on fuel combustion to generate mechanical energy. This allows them to operate for much longer periods compared to batteries used in electric systems. However, this advantage comes at the expense of overall efficiency, as internal combustion engines typically achieve efficiencies ranging between 20% and 35%, due to significant energy losses in the form of heat and noise. From a practical standpoint, experiments have shown that drones equipped with electric motors perform better in short- and medium-range missions such as aerial photography, surveying, and civilian applications, as they provide higher stability and more precise control. On the other hand, drones with conventional engines excel in long-range missions or those requiring extended flight duration, such as certain military applications or heavy payload transportation. Weight is also an important factor in this evaluation. Electric systems are characterized by simpler structures and lower weight, making them easier to integrate into small and medium-sized drone designs. In contrast, conventional engines require additional components such as fuel tanks and cooling systems, which increase the overall weight of the drone and can negatively affect its efficiency in some cases. Overall, the current engineering trend in the drone industry is clearly moving toward electric systems due to advancements in battery technology and improvements in energy density. However, conventional engines still maintain their importance in applications that require long flight endurance or sustained operational periods. With the continued development of energy storage technologies, the gap is expected to narrow further in favor of electric motors. In the near future, hybrid systems that combine the advantages of both types may emerge, achieving a balance between efficiency, flight duration, and operational range.