There is still the potential for significant efficiency improvements with open rotor ultra-high bypass propfan designs. https://www.geaerospace.com/news/articl

There is still the potential for significant efficiency improvements with open rotor ultra-high bypass propfan designs. https://www.geaerospace.com/news/articles/shape-things-come-open-fan-technology-championed-airbus-summit-2025 https://www.geaerospace.com/news/articles/shape-things-come-... And for short flights, battery electric or hybrid power could boost efficiency even further. Although that will depend on developing batteries with better safety and power density characteristics.