I've been doing some experimenting with an airbrush, a cheap Badger 200. One thing that bugs me is the amount of paint it uses: I can hardly paint a single 1:144 aircraft with one tinlet of Humbrol paint (suitably thinned). This means frequent refills of the airbrush, usually when I'm halfway done, so I have very little time to refill before the paint starts to dry and I get visible differences. My only other spray painting experience is with Tamiya rattle cans, and that's even worse. I tend to use two cans (about 60 ml each) on a 1:24 car body (one for layers 1 and 2, the other can for the final layer, so I won't be stuck with an empty can halfway through). In both cases I'm under the impression a lot of paint gets wasted (doesn't end up on the model).
The question is, is this better with a good airbrush? The paint reservoirs I see on modelling airbrushes are tiny.