About to paint car..

I don't have an airbrush, but I do have an old can of Pactra 'outlaw black' paint. Do I HAVE to primer/sand it before I spray on the paint? Or can I spray the paint on without primer/sanding? This is my first kit, and I realize that its not going to be my best so I am not too worried about it. I plan on buying an airbrush soon and will have it available for my next kit.

Primer will help the paint stick to the plastic. So, yes, it is recommended.