I'm not an aerospace engineer, so I can only repeat what I've seen in presentations. (I'm a software engineer at an aerospace research organization.) One speci

I'm not an aerospace engineer, so I can only repeat what I've seen in presentations. (I'm a software engineer at an aerospace research organization.) One specific area that I recall being investigated is the ability to decouple power and thrust. That is, convert some of the power generated by the existing turbines into electricity and use that to drive an electric fan in (a) non-traditional location(s). This can have complex aerodynamic interactions that I don't really understand in detail, but the take-away is that it can reduce drag and thus overall energy required for a given flight.