Affiliate relations can take many forms, from setting up unincorporated chapters or divisions of the parent organization to creating separate entities and controlling them by contractual and bylaw provisions.  From the perspective of the “parent” entity, the ability to assure the quality of the goods or services, to control the name and intellectual property, and to limit the risks of liability are probably the most important issues.  The affiliates generally want as much freedom and support as they can get to do their own thing.

In your case, it sounds as though any formal structure would be unnecessary at this time and that its implementation and operation would be more expensive in time and money that it would be worth.  The organization can control its design and distribution of the cars with a simple agreement with you. It sounds like there is little risk of liability.  It also sounds like you are working alone so that there is no need for a separate governance structure and that the costs of the product are relatively small so that there is no need for extensive local fundraising.  Unless the activity expands so that local organizations are required, it sounds like both of you would be better off if you work merely as an extension of his shop.