Medium-to-long range airliners
Medium-to-long range airliners probably face the biggest challenge when it comes to moving away from fossil fuels. Fully electric powertrains are not mature or fast enough to be suitable for long range aircraft, and liquid hydrogen is heavy and cumbersome to transport leading to serious compromises in aircraft capabilities and economic viability. It is no surprise that there are few reasonably solid plans for medium to long range airliners that do not rely upon fossil fuels. An aircraft is considered a medium-to-long range airliner if it can seat at least 100 passengers and take them over 1000nm.
TU Delft Flying-V
Image credit: TU Delft Flying-V media kit
Primary location: Delft, the Netherlands
It may seem a little odd to have a university project in this list, but the Flying-V project has the ambition to eventually produce this aircraft by 2040 and has the backing of some serious partners such as Airbus and KLM. For propulsion, both traditional and liquid hydrogen powertrains are being considered. The range using hydrogen as a fuel source would be less than that of a design using conventional jet fuel however.