There has been speculation about why Sergey Brin is building a giant airship. You can read about it here:
Sounds to me like he is building a yacht of sorts. But I wouldn't worry about whatever he's doing.
The art of airship flying died with the crash of the Hindenburg. All US airships suffered a similar fate - they also crashed, mostly from weather induced problems. No matter how many sensors and computers he uses to "control" his airship, its overall response never will be fast enough to cope with the rapid changes one can expect in Earth's atmosphere.
Therefore it's quite likely that Sergey's airship eventually will crash, too.
And wouldn't that be a shame.