I am no longer an AARP member. Was in the past, but I wrote them a proposal to do an article on the Control Line Vintage Stunt Contest held every March in Tucson. It is one of the major concentrations of AARP and potential AARP members on the planet.

I made a pretty good presentation, but they were not interested; so I quit their organization in high dungeon and disgust.[>:]
So far as getting young people into model aviation. I would go after home schoolers. They have an organization and network, so can be found. Those parents are dedicated to doing for their kids, their kids do not have the rigidly organized schedule of extra-curricular activities, and the parents are on the look out for good learning and socialization experiences.