If you search on YouTube, you should be able to find videos by painters who paint a figure almost entirely using an airbrush.
I find it tricky enough to master painting them by hand, and I'm still too much of an airbrush novice, to use an airbrush to paint my figures.
I do want to try it on larger figures, though. I have some anime figures in my stash, and one in progress, where an airbrush would be useful to lay down skin colors on large areas. I've also got a female figure which I want to paint as wearing stockings, and the airbrush can be used to achieve that effect.