[maith1]

The biggest issue for innovation in aircraft, is due to the sheer capital it requires to develop both jet engines and the aircraft, which results in companies developing these separately. For there to be more innovation in the space there needs to be closer alignment between aircraft manufacturers(Airbus, Boeing) and jet engine manufacturers (Rolls Royce, GE, P&W). There's talks of blended wing bodies etc, which would improve aerodynamic efficiency but I can't see anything like this happening given the way the industry is set up.