Comment by NikolaNovak

I guess it depends. I understand some ultralights and new airplanes may be efficient. But it is my understanding that a Cessna 172 lycoming is basically 50-70 years old, depending on how you count, and horribly inefficient, and completely prevalent. Faa certification for new engines is such that innovation is stifled. I mean it took the industry what, 3-4 decades and counting, to phase out leaded fuel which we all agree is God awful :-0