When it comes to airbrushes you get what you pay for. Those horror freight ones are absolute junk. You can buy a GOOD airbrush from Iwata for around $60, they of course go up, but that is a good all around airbrush, in fact the entire shrike that e-dave showed pics of was done with the iwata revolution. A $60 airbrush, So was this turbine heli canopy.



You can paint on ultracote as well, but you have to sand it and then clear coat it, it's a lot of work but it's doable.
Here is my old Legend 5 that I airbrushed some graphics onto the ultracote.