> Sadly, aviation has enough political muscle that they're still allowed to use it. Does it? GA is a shadow of its former self. There's already a substitute.

> Sadly, aviation has enough political muscle that they're still allowed to use it. Does it? GA is a shadow of its former self. There's already a substitute. But it's precisely how small general aviation has become that's stifling the transition. The volume of avgas made today is already pretty small, compared to other gas users, and there's ony a handful of plants that can make it. Then there's all the small airfields with existing avgas pumps. Without a big push, it will take time. The fastest way would be with a carrot; the stick can come later.