Two problems spring to mind here. Firstly any kind of travel rationing will almost always hit the poorer in society, which in turn will lead to more of a social division, which in turn will lead to malcontent, which will eventually lead to violence, possibly even war. Secondly, limiting travel will make countries, cities, towns, rural areas more isolated. This in turn will lead back to people being more & more suspicious of people from outside their communities, which in turn will lead to more of a social division, which in turn will lead to malcontent, which will eventually lead to violence, possibly even war. See a pattern forming yet?
Believe it or not, but travel brings human beings together, helps people better understand each other & our individual ways of life, customs, even religions. Without that we are far more likely to wage war, and with the weapons available to quite a few nations now, that could bring then end of the world, not in decades but in minutes. And if this sounds overly dramatic, its meant to be because history is full of the devastation caused by human beings fighting because they didn't trust or like another nation. So travel, the ability to reach beyond our own pre-set boundaries is good, maybe even essential for the human race to survive.
If you really want to tackle man-made climate change, & man-made pollution (something that seems to have taken a back seat these days) then take for example a real bug-bear of mine, food waste. In the west in general we throw away a third of all the food we produce (closer to 40% in the US), often without it even coming out of it's packaging. So we could, for no real cost to personal budgets, reduce our wasted food to as close to zero as possible, feed the homeless with what was left unsold, and still reduce of food carbon footprint by 30%. Plus as a bonus we would also reduce of need for packaging by a third, reducing the amount of plastics made & therefore associated pollutants, and reduce by the same the amount of plastic that we either throw away into the oceans or have to recycle.
Now that would make a real difference. And all it needs is for people to understand how to buy just enough, and when & how to use the food available effectively. It is the ultimate first world no-brainer.