Aerospace propulsion systems utilizing gas turbines have been in use for nearly a century. The staggering amount of technological advancements made in improving the efficiency and performance of gas turbines have resulted in some of the best examples of human ingenuity. Unfortunately, the conventional gas turbines are reaching the limits of their performance, and this warrants innovative concepts to respond to the ever-increasing performance requirements. Pressure Gain Combustion is such a technology that has gained momentum in the recent decades, with advantages such as higher thermodynamic cycle efficiency and lower specific fuel consumption. The propulsion devices based on PGC also support the use of hydrogen fuel, making them attractive to a carbon neutral global trend. But this technology is yet to be realized in aeronautical propulsion sector. In this thesis, the application of Pressure Gain Combustion for aeronautical propulsion is studied. The study has resulted in dynamic modelling of aircraft engines with/without PGC technology, along with part load performance evaluation. In addition, the research work also resulted in the development of dynamic models that can be applied both standalone open-loop compression systems & closed-loop compression systems for heat pumps, and reduced order modelling methodology for rotating detonation combustion. A simple bleed scheduler system for PGC aircraft engines is also developed during the research thesis, which would assist in the component level development studies of PGC aircraft engines in the future.