That's a fascinating idea. I googled it and came upon https://en.wikipedia.org/wiki/Vacuum_airship https://en.wikipedia.org/wiki/Vacuum_airship and https://scho

That's a fascinating idea. I googled it and came upon https://en.wikipedia.org/wiki/Vacuum_airship https://en.wikipedia.org/wiki/Vacuum_airship and https://scholarsbank.uoregon.edu/xmlui/handle/1794/22370#:~:text=The%20Vacuum%20Airship%2C%20or%20Null,in%20nearly%20all%20conventional%20airships https://scholarsbank.uoregon.edu/xmlui/handle/1794/22370#:~:.... Sounds like it's feasible but a materials/engineering challenge.