Comment by fragmede

There's always the air-gasoline route. That's right! With enough chemical engineering and materials science, we can extract jet fuel from air and water. You extract out CO2 from the air, and H2 from water. You turn the CO2 and hydrogen into carbon monoxide, and then Fischer-Tropsch chemistry and some other magic gets you hydrocarbons out the other end! The problem is the economics of that process can't compete with oil from the ground.