As long as your fuel tank doesn't like it's fine. Burnt methane is back to CO2.
What this whole thread boils down to is we need a huge amount of nuclear power, after which rather than worrying about all 3 of "safe", "dense", "efficient", we can just worry about the first 2.
Seriously, if it takes 1000x the energy from nuclear power to fix enough C02 to make conventional jet fuel from the air, that is fine. That's something we can optimize on a leisurely basis when we are not worrying about global warming.
[1] https://www.edf.org/climate/methane-other-important-greenhou...