What do you mean? The fuel itself should be carbon neutral, even if it requires extra energy to create. I don't see any reason you couldn't make carbon neutral bio fuel, although I'd net on syngas instead.

Growing food and converting it to fuel is not carbon neutral. Farming is very resource intensive at the scales needed. In fact, it is literally the same idea as carbon capture, but via biology instead of synthetic. As a result, it is entirely a bad idea.

Biofuels today have issues, but there's no fundamental problem preventing them from being green. It's just a side effect of shoehorning them into our existing agriculture systems.

In the future when we have more solar power than we know what to do with during the day it may become economical to run the Sabatier reaction with hydrolyzed seawater and atmospheric CO2 to make methane, which can be burned in a lightly modified aircraft turbine.

That isn't biofuel. That's synthetic fuel.