Why aren't they trying to control emissions on aircrafts?

Yeah, my dad noticed that years ago working for Du Pont. But to be fair, newer engines are being designed all the time with greater efficiency in mind. That's what the newer fanjets are all about. And there's no reason they can't fly jumbo jets on biodiesel. What do you think jp fuel is? Basically, it's refined diesel fuel. As to rockets, while those strap-on boosters aren't great for the air, the main engines run on hydrogen and oxygen. They don't GET any cleaner.