For a lot of things, flying included, economies of scale play a big part. In very simple terms, a flying operation would be more efficient if it served more people in one go. That being the primary motive for airplane manufacturers busy making big-ass planes. But there’s something much bigger, even if it is just a concept. The Airborne Metro is a gigantic aircraft that could fly thousands of people to their destination.
It would likely be huge enough to allow aircrafts to land and take off from its back, and allow them to dock and taxi. Powered by nuclear energy, the aircraft could stay in flight for thousands of miles, while smaller aircrafts take off and land on its back, and ferry passengers to and from nearby destinations.
An idea like this could be very successful for some of the most highly trafficked routes in the world. Estimates say an overall fuel saving of about 40% would come along for a 600 mile trip, and it could go as high as 80% for a 6000 mile trip.
Of course, there’s still a lot of time before we could even begin to build something so huge and advanced, but concepts are always a good start for things that may be real in the future.