You say that in the past tense... But pretty much every propeller plane worldwide still uses the stuff...
Only in piston engines, which are a minority of propeller planes. Most commercial propeller aircraft are turboprops, and they use jet fuel. And diesel engines are slowly taking over from gasoline in piston engines.
Only in piston engines, which are a minority of propeller planes. Most commercial propeller aircraft are turboprops, and they use jet fuel. And diesel engines are slowly taking over from gasoline in piston engines.