If flying cost twice as much, then people would, at the limit, be able to fly half as often as they do now.

If they valued their vacation more than other stuff they could just do it anyway, assuming we're talking about the same "middle class" (e.g. not the poor that spend to their max).

But yeah, the whole point is to reduce luxury travel. Jetset vacations are a luxury. We might be able to make them cheap and clean in the future, right now offsetting has a real cost.

The current shinkansen reaches 200mph, with in-development versions going faster.

Distance from NYC to LA is 2790 miles (by highway; the straight-line distance is shorter). That’s a bit under 14 hours at 200mph.

That’s pretty much the worst case; most people aren’t flying cross-country on a regular basis, and regional flights (e.g. Columbus to Chicago) are a big business.

Obviously real trains would be slower than peak shinkansen speeds, but like most train opponents, you are severely exaggerating your argument.

It isn't just about choosing to take a pleasure vacation or not, but seeing close family and friends that often aren't in the same state.