To achieve the climate goals in aviation, the energy demand for the transport task must also be significantly reduced. In this context, propulsion systems play an essential role, as there is still a high potential here, which is particularly evident in the WET project. At the same time, the concepts for new propulsion systems require a much higher degree of integration into the overall aircraft and must therefore already be included in the concept phase of an aircraft development. This also offers the opportunity for stronger synergies between different new technologies on both the aircraft and the propulsion side, which ultimately leads to the efficient overall concepts.