Placing paint pots on airbrush

It could be done with a color bottle attachment. But I won't recommend it because the paint would be too thick (and it's good to keep your paint pots set up for brush painting.)
But try a bottle rather than a cup for a larger source of diluted paint-unless you have a gravity feed airbrush. :-)

Micromark makes the botle lids with the correct sizes for several paint jars.

http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=60936

But as Trowlfazz said most need to be thinned to use in an airbrush. The only exceptions I know of are colors you use a LOT of. I know some here who paint let's say WWII US Navy AC that thin their Sea Blue in the bottle and spray directly from it since it is a color they use often.

I don't believe there is an adapter for Tamiya paints as they are SO thick usually as to be near impossible to spray directly from the jar......

Hang onto your empty Tamiya bottles. They will screw right onto a Badger air cap. You'll have to shorten the tube some though.