a plane traveling at 150 mph at 15 pounds impacting your head would make you no less dead then a plane at twice the weight

The difference may be that a 15 pound plane may kill or hurt 1-6 people and a 100 pound plane may kill or hurt a dozen or more, Lets face it, if it were a Piper Cub that hit the World Trade Center , it would still be standing although it wasn't just the impact that brought it down, the impact alone probably killed many people , a Piper Cub would probably just bounced off or got stuck on the side causing considerably less damage.

The sliding scale for insurance opens a whole another can of worms, and a butt load of additional work , If the big planes should cost more , them the small slow flyers should be less, and rubber power almost nothing, Then We would have to constantly up date our change in interest, You would probably have to register every plane you own build and buy so the AMA can keep everyone honest.

I am up for any Ideas, But so far none have fit the bill any better than what we already have.

The Fact is we are talking about potential Liability, an eye poked out by a Park flyer will cost us as much as an eye poked out by a glow engine, but getting sued by 1 to say 6 people is less costly than 12 or more.