Well, then don't cross oceans then. Travel long distances rarely. It's not a human right to get cheaply to the other side of the globe. And with recent breakthroughs in electronic communications, we don't have much need for vast majority of travelling. Close-but-living-far-away relatives dying or getting married happens only so rarely.
If we want to fight pollution big time, ultimately we have to reduce amount of traveling. At least till we get nuclear fission working and batteries with good energy density. Entirely new ways to make trains and planes themselves.
Sure, we'll just all go back to medieval ways of living! That sounds like a great idea! Why travel when you can just stay at home and play video games all day!
Not flying long distance does not mean staying home. Unless you live on a 500m radius island in the middle of an ocean with next land mass thousands of kilometers away.
If we want to fight pollution big time, ultimately we have to reduce amount of traveling. At least till we get nuclear fission working and batteries with good energy density. Entirely new ways to make trains and planes themselves.