Hybrid and electric cars sell because they lower operating costs for the owner. Designers and manufacturers sort out ways to increase efficiency, including streamlining, using low-rolling-resistance tires, and making structures lighter. An added technology, boundary layer ingestion (BLI) may add to aircraft efficiency. NASA and industry leaders are working on equivalent solutions for aircraft, and airplanes will end up as different from today’s designs as Toyota Priuses and BMW i3s are from Ford Falcons or Chevrolet Corvettes. NASA proclaims, “An aviation renaissance, one focused on energy efficiency and economic impact, is on the horizon, and it’s changing how engineers look at aircraft power and design.” Jim Heidmann, a manager of NASA’s Advanced Air Transport Technology Project (AATT), says, “I feel we are at a tipping point in commercial aviation. We are exploring and developing game-changing technologies and concepts for aircraft and propulsion systems that can dramatically improve efficiency and reduce environmental impact and accelerate the introduction of new aircraft.” Think of …