A few things come to mind from more modern aircraft like the 787/A350: Fly by wire (flight envelope protection), electronically actuated control surfaces (less

A few things come to mind from more modern aircraft like the 787/A350: Fly by wire (flight envelope protection), electronically actuated control surfaces (less hydraulics / reduced complexity), bleedless engines (greater efficiency), greater use of composites (less weight), modern wing design using computational modeling/optimization (possibly more efficient), and essentially as large of a turbofan fan as you would like