I have a 24l Fragram compressor, airbrush & gravity feed spraygun. I want to spray small Auto body parts(plastic). Will the compressor maintain?
By "maintain" I'm going to assume you are asking if it will provide enough air flow to do the work you need to do. If this is right, we'd need to know if your spray gun is a High Volume Low Pressure (HVLP) type spray gun. If so, the compressor should do you just fine. I would bet, though, if you are going to be doing a lot of painting with this, even with small parts, you'll want to get a better/bigger compressor at some point. This will probably wear out fairly quickly with continued use, especially if the parts get bigger over time. This type of compressor is not really rated for continued use, but for short sporadic use.
The compressor would be WAY more than enough to service the air needed for an air brush any way you look at it.
If you are actually doing the work, you'll want to ensure you have a separator/drier/filter attached to the air line to ensure you are only getting air out of the hose and not contaminants.