Exactly. Flying for sport is expensive as it is today because safety has to be a priority (as it should). Add a requirement for new engines or major overhauls o

Exactly. Flying for sport is expensive as it is today because safety has to be a priority (as it should). Add a requirement for new engines or major overhauls on old planes and the cost will spiral out of control. Besides, leaded fuel was a problem when literally every single car on the street was burning it. The total volume of fuel consumed by aviation piston engines is a joke compared to that.