What kind of airbrush is it?
When you sprayed the alcohol did the spray stay the same or did it start out low and get higher? And did you try spraying water after you sprayed the alky? I'm wondering if there was something dried in the nozzle that the alcohol may have dissolved.
I'm not familiar with that compressor, but is there a regulator or any way to adjust the pressure on it? Perhaps it is set too low. Is there a bleed hole (can you hear air escaping when you do not have the airbrush trigger down)? That would affect the volume of air. Is there a leak in your hose connections? Try putting some soapy water on all the hose connections all the way from the comressor to the airbrush. If there is a leak air bubbles will form.