Is my airbrush and compressor not compatible?

I'm betting you have a 1/8" vinyl hose and a 1/4" compressor. Like this.

You should be able to find one at any hardware store or hobby store. About 4$. Get a roll of teflon tape (found in the plumbing section <$2) to seal the threads, and you should be in business.

I have on my moisture trap to fit my vinyl hose, it's at the bottom of the picture.

If you get a braided hose, they almost always come with the right fitting, but that will cost more than the adapter. 

This may be what you need. If the compressor hose fitting is much larger than you hose then that fitting is probably a 1/4" pipe fitting. This adapter will let you hook up. Look half say down the page.

http://www.dixieart.com/Hoses.html#anchor287927

You can find these in most of your better hobby shops.

Edit: DOH! Bgrigg beat me to it.

 

Adapt and overcome....so said Gunny Highway. Hardware store or plumbing supply house should have the brass adapters to solve your problem. When you change brands of airbrushes you might run into this again...adapt and you're in business.

I bet you can solve this problem with enough duct tape. Any problem can be solved with enough duct tape, just use more of it... :)

Actually, it's not as silly as it sounds. If you have pressure regulator before the connection, air pressure will surely be small enough for duct tape to provide perfectly secure and functional connection.

That said, there should be plenty of adaptors in a good hardware store. Measure the size of both connectors, and check your nearby hardware store.