Travel requires a great deal of energy - whether you go by car, by bus, by train or plane. We'll likely be using hydrogen as our main energy for transport.
Hermann E. OttOur resources will diminish in the coming decades at a time when hunger for energy grows dramatically in China and other parts of Asia. Eventually, it will just be impossible to fly - normal flights will become as expensive as flying with the Concorde.
Hermann E. Ott