That's according to a bombshell new report from Bloomberg Businessweek, based on conversations with numerous sources.

Page reportedly also owns a secretive startup called Zee.Aero, which launched in 2010.

The billionaire exec has apparently spent more than $100 million of his own money on the company, which is based in Mountain View, California, (near Google's HQ) and now employs nearly 150 people.

And that's not all: Page is alsoreportedly funding a second flying-car startup called Kitty Hawk. Kitty Hawk works independently from Zee.Aero, but has similar goals. (It's not clear how much Page has invested into Kitty Hawk.)