Regulatory changes were a big part of that. IIRC, manufacturers were ruled to be liable for accidents, and they all pretty much stopped making planes. So now pl

Regulatory changes were a big part of that. IIRC, manufacturers were ruled to be liable for accidents, and they all pretty much stopped making planes. So now planes are rare, very-old Cessnas cost what several cars do instead of what a single car does, and development is so stagnant that leaded avgas is still a thing.