We propose a prototype design of a propulsion thruster that utilizes air plasma induced by microwave ionization. Such a jet engine simply uses only air and electricity to produce high temperature and pressurized plasma for jet propulsion. We used a home-made device to measure the lifting force and jet pressure at various settings of microwave power and the air flow rate. We demonstrated that, given the same power consumption, its propulsion pressure is comparable to that of conventional airplane jet engines using fossil fuels. Therefore, such a carbon-emission free thruster could potentially be used as a jet thruster in the atmosphere.