Google co-founder Sergey Brin is building an airship in one of NASA's hangars at the Ames Research Center. The dirigible reportedly looks like a zeppelin and could be a hobby of the billionaire. Or it could be a project for Alphabet's biggest subsidiary.

According to Bloomberg, Brin has long been interested in airships. This supposedly began since he started visiting the NASA research center located beside Alphabet Inc.'s domicile in Mountain View, California. The Google co-founder decided to build his own Zeppelin-shaped aircraft after seeing a photo of the USS Macon, a dirigible constructed by the U.S. Navy in the 1930s.

Google unit Planetary Ventures took over some of the huge hangars at Ames in 2015. It is in one of these that former director of programs at NASA Ames Alan Weston is said to be heading Brin's pet project. Already, his team of engineers has assembled the metal foundations of the airship. Although it is still a skeleton, it is taking up much of hangar space by now.

However, it still remains unclear whether or not the airship project is Brin's private venture or a Google-approved undertaking. The Verge noted that the Google co-founder had nothing to say about the endeavor when asked for a comment by another news outlet.

Weston also declined to comment, but the former Air Force engineer once mentioned the viability of airships as cargo transport crafts in an interview in 2013. He said the crafts could potentially be more fuel-efficient compared to planes. In addition, they could carry their loads directly to the area in need rather than drop them off at transport centers.

Many Silicon Valley companies have been struggling to build airships for years. Even Google X, the company's experimental arm, attempted to create an air freight. But in 2016, Project Calcifer as it was called, was shelved.