When an airplane is full, the energy used to travel a given distance compares very favourably with driving an economical car. Primary energy use is less since airplane turbofan engines are more efficient than car engines. Even airplanes with propellers driven by petrol engines are more efficient than cars as the engines are operating at near-peak rpm and producing a higher proportion of the rated power. Air travel uses a lot of energy because it makes travelling long distances easy, even if not very comfortable. The airplane is limited by the weight it can carry, which puts a limit on how tightly the passengers can be squeezed together. Given that drag will always be a factor in high-speed transportation, even for ground transportation, energy use can be minimised by reducing the cross-sectional area and squeezing more people into even smaller spaces, such as in the hyperloop.
Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.
If you think you should have access to this title, please contact your librarian.