We also need to consider the logistical challenges of aviation. An airplane carries all the energy required to reach its destination. Of course, road vehicles also need to carry fuel to drive from A to B, but an airplane has to lift that weight and hold it in the air. Consequently, the impact on energy consumption from additional weight in an airplane is significantly higher than that of a car or any other ground vehicle. This requires airplane technology to be lightweight. As of today, liquid fuels are the most efficient energy storage, with an energy density 50 times higher
than present batteries, making the latter an infeasible solution for aviation. New hybrid concepts that combine electrical and jet fuel engines are in development, such as the latest announced joint project E-Fan X
by Airbus, Siemens and Rolls Royce. The concept will be a new technology milestone for the industry, driving efficiency and progress to a fully electric airplane in the long term.