I think very few bits here are actually stored in-flight on the copper/fiber/radio at any time. Most of them are probably stored in various buffers of networking equipment (which are ordinary semiconductor RAM). It would be interesting to see someone do an actual breakdown for, say, a transatlantic link.
My gut feeling says that only geostationary satellite links have any significant number of bits in-flight.
My gut feeling says that only geostationary satellite links have any significant number of bits in-flight.