As I recall, Musk says that if you can double current energy densities, electric airliners become feasible. That could happen in some decades.
If that doesn't happen (or if he's underestimating what it takes), then I figure the solution for air travel will be synthetic fuels. Synthetic fuels are not very good right now simply because it takes a lot of energy to make them, but if energy is cheap and abundant because, say, the world is covered in solar panels, it's less of a problem.
If that doesn't happen (or if he's underestimating what it takes), then I figure the solution for air travel will be synthetic fuels. Synthetic fuels are not very good right now simply because it takes a lot of energy to make them, but if energy is cheap and abundant because, say, the world is covered in solar panels, it's less of a problem.