If the fuel is synthetic anyway, uh can be made better than kerosene.

Also, we have a huge amount of free nuclear energy, daily delivered from Sun, about 1 kW / m². It is nit stable enough for electric baseload, but, depending on the process, may be adequate for fuel synthesis.

North of Sahara may become a primary source of jet fuel, given its vast amounts of insolation, cheapness of the land, and access to seawater. Not exactly tomorrow, though.

Better than kerosene how? You're not going to get higher energy density without increasing safety risks.

Not exactly tomorrow, but we're facing a problem today. What are we supposed to do to reduce CO2 emissions between today and the mythical day we will have unlimited amounts of synthetic fuel available shipped by tankers from Morocco?

Well, if we ever figure out fusion, we could get the enormous amount of energy part.

Ok; until then, we have to reduce CO2 emissions by 7% each year from now until we reach net zero in 2050. Even if we figured out fusion today (highly unlikely), it won't be deployed at scale by then (a modern fission reactor takes 10 years to build). So there are two choices really: progressively scale down the aviation industry, or ignore the climate crisis and let 100s of millions in poor countries die from climate-related causes.

We could actually do that using fission alone, since we have we enough fuel for 70,000 years or so, and nuclear waste is free of green house gases. It would just be very expensive up front, as nuclear plants tend to be.

Anyways, this is the way France is going.

If you don't keep the scale, it would never get cheaper. Airlines struggle with profitability as-is, no point imposing additional undue burden.