Vacuum airships have a long history: "First proposed by Italian Jesuit priest Francesco Lana de Terzi in 1670"[0]. The O-Boot project referenced in some replies aims to fly its first prototype on 13 December 2019 because that is the anniversary of the birth of Francesco Lana.

We'll see, but maybe it is like nuclear fusion energy - always just around the corner.

[0] https://en.wikipedia.org/wiki/Vacuum_airship