Disclosed are systems, methods, and devices for generating radicals in an air stream at the intake of an internal combustion engine, as well as increasing the thrust of such air streams into the engine. A plasma generator including plasma actuators, dielectric barrier discharge electrodes, or both is positioned in the intake stream. Plasma actuators are disposed on the interior surface of the plasma generator, exposed to the intake stream. Dielectric barrier discharge electrodes protrude into the intake air stream. Plasma, preferably DBD plasma, glow plasma, or filamentary plasma, is generated in the air intake stream, creating radicals in the stream, mixing the radicals in the stream, and reducing drag while increasing thrust of air in the intake stream. A concentric cylinder can be further disposed in the plasma generator, with further plasma actuators, dielectric barrier discharge electrodes, or both, on the interior and exterior surfaces of the cylinder.