Larry Page, one of the cofounders of Google who is now the CEO of its parent company, Alphabet, has secretly spent more than $100 million to develop flying cars.

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.

Larry Page, Google cofounder and CEO of parent company Alphabet. David Paul Morris/Bloomberg via Getty Images 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 also reportedly 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.)

This isn't all just hypothetical, either. Zee.Aero has two prototype aircrafts based in a hanger nearby, Bloomberg says, which take "regular test flights." Its vehicles are electric-powered.

The diagram above, from a patent originating in 2011, was an early design, Bloomberg reports. It is now pursuing a "simpler, more conventional-looking design."

The long-term vision for flying cars is to build a light aircraft capable of acting in a similar way to earth-bound cars. Designs made by Zee.Aero use propellers for vertical take-offs — essential for saving space — and some diagrams even show the vehicle wings folding up so it can fit in car parking spaces.

Zee.Aero's website doesn't give much away. "Based in the heart of Silicon Valley, Zee is developing a revolutionary new form of transportation," it says in a call for job applicants. "Working at the intersection of aerodynamics, advanced manufacturing, and electric propulsion, we provide a stimulating environment where creative employees can explore new challenges."

Zee.Aero's website. Zee.Aero

Page has apparently worked hard to keep his involvement in Zee.Aero secret. Early in the company's history, when it was based in a building that he rented the upper floor of, he wasn't even called by his true name, Bloomberg reports. Instead, employees only said "GUS" — short for "Guy UpStairs."