The process is straightforward:
1. A lot of cheap solar energy, from the best location.
2. Electrolyse to produce hydrogen.
3. Capture CO2. Either from air or from carbon intensive processes (e.g. producing cement).
4. Use Sabatier reaction to bond CO2 and hydrogen to produce carbohydrate fuel.
5. Since we use same amount of CO2 to produce as there will be burn this carbon neutral fuel.
It's much easier to do it at scale, than redesign, get approved new planes, replace all existing fleets and the infrastructure. This could easily take 60-120 years, when we need to act much sooner to prevent worst consequences of global warming.
Of course, today this would not work as individual steps are too expensive. Though all of the steps could be much cheaper as solar energy panel shows.
It gives possibility for oil rich countries to transform to post carbon economy when they resources will be depleted and consumers would prefer carbon neutral fuels.
I guess all of this sovereign funds would be much better of investing in this tech than pouring money in SoftBank to do WeWork style opportunities.
Google crowd oil or solar kerosene for papers about it.