That's not feasible. You can't cross oceans in any reasonable timeframe without an airplane. Even long land trips don't really make sense by train, over I'm guessing 1000km.
My whole point here was to devise a taxation strategy to discourage passengers and airlines from flying short routes, and leave those to trains instead, reserving airplanes for the much longer routes where they're much less avoidable, and also to encourage more centralization of air travel from large cities and their airports, so that larger numbers of passengers are funneled onto a smaller number of very large jets for those intercontinental trips. Passengers would then just have to take trains to/from the smaller cities. Larger planes are far more efficient in terms of fuel per passenger per mile; much of the fuel burned in a flight is used on take-off and getting to altitude anyway, so maximizing distance and plane size means minimizing fuel per passenger-mile.
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.
