Plasma actuators of the Dielectric Barrier Discharge type are an adequate mean to increase the eficiency of propulsion systems. By controlling the boundary layer DBD actuators are able to provide increased efficiency of turbomachinery propulsion systems at diverse operating points. The operating points change as a function of the external environment conditions, namely pressure and temperature, and also of mission profile. Herein we will demonstrate that the DBD actuators are actually performing better at higher altitude. An teoretical framework will be developed and a numerical approach will be able to demonstrate their better operation as initially proposed. A specific application framwork will be considered for a differential vector thruster based on a Coanda surface.