From minute 23 to 27: “(…) transfer shear through the cans of the cells (…) like having an aluminum honeycomb with upper and lower face sheets (…) it gets crazy stiff (…) and that’s really what you want !“
Elon Musk has it pointed out again: Honeycomb sandwich construction has great advantages and is thus widely used today in aerospace industry.
It is an interesting analogy:
In 1915 Junkers built the first full metal aircraft enabling the economic breakthrough of a new way of transportation. The SpaceX Starship will however not only enable a new way of transportation, it will enable mankind to become multiplanetary.
The first description of honeycomb cores in sandwich construction for aircraft application can be found in a patent by Hugo Junkers from 1915. In Junkers patent sandwich aircraft structures with a rectangular honeycomb are shown. One of Junkers options to stiffen the steel skins looks similar to the stiffening of the steel rings of Elons starship.
Junkers Patent on honeycomb sandwich construction
Junkers Patent comparison to SpaceX, Starship photo