I have to agree with HS93, you really need to decide what you want to paint before considering what type of airbrush to get.
If your main requirement is painting of hulls & superstructures then I personally wouldn't go for an airbrush, a miniature spray gun would be far more suitable. To get a good finish on a hull , a spray pattern of a least 40mm is desirable, whilst some airbrushes are capable of giving this size, the small size of the airbrush pot can mean several refills to apply 1 coat.
mini spray guns are capable of delivering small spray patterens as well as larger ones, & tend to be easier to get the hang of using. The larger pot size, usually around 125 ml, also means that you can complete a coat in one go. another advantage of srayguns is that they can handle thicker paint types, i.e. enamel, polyurethane & car paint due to their relatively large nozzle size.
i am not suggesting that an airbrush is a bad idea, just thought it worth mentioning that other forms of spraying equipment are worth considering. I'm lucky as i have the choice of guns & airbrushes, but find i use the gun for over 90% of my model boat spraying requirements.
Hope this helps rather than confuses. Glenn.