Car ferries in the skies: The rise and fall of the Aviation Traders Carvair
https://edition.cnn.com/travel/article/aviation-traders-carvair-plane-cmd/index.html
When we consider each space that each passenger can occupy, it's much bigger than that a passenger on a first class seat can occupy.
It means fare for transporting vehicle is much more expensive than flight fare for the first class seat.
Under such a fare system, people would prefer to using rental cars.
