I suspect that a lot of people will be opposed or indifferent to the idea of life extension until such a point that the technology is incontrovertibly feasible. And by that point, there'd no longer be any need for public approval of life extension.

We in the life extension community might increase the effectiveness of our marketing by explicitly conflating life extension, healthspan extension, and the promise of experience a much, much better future. In other words, eternal life in heaven. In too many conversations once I raise the possibility of life extension, the next objections are either, Why would you want to live forever as a frail old person? or How will we feed all those humans on earth if no one dies?

Perhaps I'd pique more people's interests if I led with, "the next 100 years are gonna be so great: we'll cure all diseases and have vacations on Mars and no one will have to work any more. That's why I'm working on biotechnologies that will reverse the aging in people today; so that we can all enjoy the wonderful things that are yet to come."