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.