If you\'re thinking of painting a mini completely using an airbrush - basecoats, then the highlighting and shading sprayed on in the same way that you\'d do it with a brush (i.e. choosing which fold to paint and doing it individually) then no, you can\'t really do this. It\'s possible in theory but in practice it\'s very difficult and requires a really good airbrush used by someone who really knows how to use one.
Even at that there\'s a lot of masking needed and the additional effort involved would put most people off (because, quite frankly, it can be a pain in the rear - it can take more time than the spraying!).
But you can at least do basic shading using an airbrush, even at mini scales, by painting light from above and dark from below in a general way, over a basecoat. Then you just need to refine and add details by brush. Masking is still tedious though, just to warn you.
Lots of the work in my gallery is done this way but these two Hornet figs: http://www.coolminiornot.com/86772 and http://www.coolminiornot.com/86771 are the two smallest things I have pics of so you can see how it can work at those kinds of sizes.
Note: this won\'t be possible with all sculpts, since it\'s so dependant on the spray being able to get to where you want it to go and raised arms, a shield, even a large helmet, could block the flow of paint and leave gaps in the coverage. So, definitely workable for simple figs but maybe not for something complex or dynamic, pose-wise.
Einion