Long thought impossible, O-Boot has proved that vacuum levitation is possible using complex carbon structures. This allows for something like a dirigible based not on lighter-than-air gas, but rather via creating a true vacuum. They plan to build an airship for eco-friendly transportation, and are committed not to allow access by militaries.
This project seems to have flown under the radar, with a crowdfunding campaign apparently failing some time ago. I would love to see the project come to fruition. My mind is wild with the possibilities of vacuum levitation. The size of the object required appears to be very small in comparison with gas-based dirigibles.