Considering historical technology adoption in aviation and the entry into service dates for advanced airplanes, the majority of today's planes could be replaced with more efficient versions by 2050. New plane designs including Boeing's 787 and the Airbus A-350 require about 20% less fuel than baseline airplanes. Using a stock turnover model, we extrapolate these efficiency gains to the relevant U.S. airplane stock. Further efficiency gains come from adoption of “next-generation” airplane technology with 45–70% higher efficiency than 2010 models. These superefficient planes include blended-wing body concepts and strut-braced wing designs. Blended wing body designs in particular are most likely inspired by gliding tree and vine seeds like the Javan cucumber (see link) whose 5-inch seeds can glide hundreds of yards.
See Reinventing Fire Transportation Methodology for modeling details link
Walker, Matt. 2009. "Vine seeds become 'giant gliders'."BBC Earth News. link