In my thesis, the beginning of the jet engine and the pioneer inventors are discussed. the contrebution of Hans Von Ohain and Sir Frank Whittle, and their efforts were illustrated briefly with their impact on the industry. The pre-jet era was described when reciprocating engines were prevalent on aircraft designs. Early jet designs such as Turbojets and pulse jets were explained, and the impact on fuel economy presented by further developments giving birth to Turbofan engines was emphasized. Supersonic propulsion jets were explained, such as Ramjets and Scramjets, and a comparison between them was made. A scientific thrust calculation of an Ideal Ramjet engine is presented with a calculation sample. Airlines future expectations from engine manufacturers was discussed with three examples of the most advanced engines in the making or already in service.