> has been since the nineties There's still not a lot of ceramic fiber in use in the engines. That's a pure weight reduction and fuel efficiency increase, up

> has been since the nineties There's still not a lot of ceramic fiber in use in the engines. That's a pure weight reduction and fuel efficiency increase, up to the point that NOx emissions can't be controlled. Given the rapidly advancing VTOL autonomous drone tech, harbor tug concepts may yet make an appearance. The funding for this could be driven from rescue aircraft, short range powerful VTOLs optimized to go pluck a struggling aircraft out of the sky and put it on the ground. The obvious evolution of that is ditching a lot of the landing weight. Reinforced undercarriage, landing gears, high-lift devices almost all exist to be used in a very short segment of the flight. Unlike roads, automation in the air has quite a bit less variability to deal with. Would you rather pilots try to put a plane with a mechanical issue on the ground by skillfully manipulating throttles or let an overgrown DJI take a swing?