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. An aircraft is considered a medium-to-long range airliner if it can seat at least 100 passengers and take them over 1000nm.

At this point in time there are only concepts in this space, but no designs that appear to be in serious consideration for near-term production.