ABSTRACT
While commercial aviation is not among the worst polluters, it has the potential to become so. The dominant sector is long-range commercial aviation. The time needed to attain zero-emission long-range aviation is lengthy, requiring designers and operational managers together with fuellers to start now. There is a separate issue of returning existing aircraft back to service with a carbon-neutral sustainable fuel made from waste, or from reclaimed CO2, captured directly from the atmosphere. Long-range zero-emission aircraft must run on liquid hydrogen, but this requires a radical airframe design to accommodate the huge volume of liquid hydrogen. Much work is needed to optimize the design to meet all requirements. For ranges up to 2000 NM, there are more choices, including fuel cells with electrical drives to fans placed to give the best performance. For smaller aircraft flying more slowly, vertical take-off and landing becomes realistic and creates new markets, taking over the role of helicopters but with added speed and range at a much-reduced purchase price and operating costs. Such air taxis might hit the luxury limousine market.
