I get this recurring dream of a retrofuturistic world where intercontinental travel serviced by nuclear-powered ocean liners. For nonproliferation reasons, there's only a handful companies operating them, one for each theatre. It takes ~4 days to get across the Atlantic, so some amenities are inspired by cruise ships, but optimized for less crew. It's an intriguing dream, but in our current world the economic and regulatory barriers around nuclear propulsion for civilian use make it impractical. More on this later.
I believe economic forces and regulations will be the primary drivers of changing modes of transport, so if it makes economic sense to keep operating jet fuel aircraft, that will be an option for those who can afford it and don't have misgivings about it. But for planning and resilience, there's value in envisioning how a world with very limited jet fuel air travel would look like, and whether portions of its role ought to be taken over by other modes of travel, or if societies merely need to adjust to its loss.
Our world's globalized economy greatly depends on the movement of goods and sometimes people, but for goods, the pace of water transport is often good enough, coupled with its much lower cost per amount and time. Much of this transport uses some of the lowest grades of fuel you can get from fossil oil. To change this, the price of these fuels would have to soar or the fuel would need to be banned. Let's suppose this extreme case comes and fuel oil is no longer an option. A rapid migration to nuclear propulsion for merchant fleets is both politically untenable and economically improbable. Solar/battery propulsion doesn't have the energy density, which leaves wind-like propulsion as one of the only contenders, with the others being simply higher grades of hydrocarbons like gasoline and compressed gas. One's carbon-free, slow, and presents a significant change in show ships are built, while the other needs changes only to the engines, fuel lines, and fuel tanks, re-uses existing industrial expertise, and maintains the pace of travel -- but isn't carbon-free. Which one do you think companies would chose?