Los Angeles, 2043: An optimistic scenario for transportation

It is a sparkling, sunny August morning in 2043, as your Air China flight from Beijing touches down gracefully (and almost silently) at LAX. The sleek plane is one of a new generation of hydrogen-powered wide-body jets manufactured by Commercial Aircraft Corp. of China -- the kind of innovation that helped the state-owned company sail past Boeing and Airbus in the 2030s to become the world's largest aerospace group. Starting with the Inflation Reduction Act in 2022, the last two decades have seen massive efforts to clean up transportation all around the United States and throughout the world. Back in the early 2020s, transportation accounted for 29% of America's greenhouse gas emissions, but that number has been steadily dwindling to almost zero -- resulting in cleaner cities everywhere. Not only have electric and hydrogen-powered vehicles replaced gas-guzzling cars, but many people have forsaken car-ownership altogether, in favor of much more economic and widely available solutions like e-bikes, robo-taxis and public transit.