It would not make sense today, but in 10 to 15 years, with climate regulations, having a carbon neutral jet fuel might start making a lot of sense.
I don't understand your rail/car replacing flying argument. There are no signs that flying is going to get so expensive that people would rather pay for it with so much of their time.
Using a process like this would essentially make the fuel simply a much better battery for airplanes than our batteries today.