One coat paint for aluminum?

Howdy,

I'm building a Savannah, and I want to keep the weight down. I'm only
planning to paint some odd shapes on the plane and leave the rest bare
aluminum. Since the plane is a simple, crude little creature, I can't see
spending a bunch of time and money on these paint accents.

So my question is: Can you direct me to a source of paint for aluminum that
does not need a primer, but just sprays right on the metal?

thanks,
tom pettit