The Biggest Problem With Flying Cars Is on the Ground - WSJ

Joby has also predicted that operating costs for its vehicles will be 86 cents a passenger mile. Dr. Trani thinks the actual figure will be between $3 and $4 a passenger mile.

That $4 per mile price is the same as a 9 passenger twin engine turboprop today. The electric air taxis can only carry 2-3 passengers.