Sergey Brin and Larry Page, both 32, splashed some of the $22bn (£11bn) fortune they made by creating the world's largest internet search engine on a Boeing 767 airliner.
The ostentatious purchase appears to be a departure for the two Stanford University computer science graduates who have mainly shunned the trappings of wealth common among American chief executives.
The muti-billionaires both drive environmentally friendly Toyota Prius cars and, when asked on the television programme 60 Minutes after Google's flotation last summer, Mr Brin said he had spent some of his financial windfall on a T-shirt.
The plane, which cost up to $15m, carried 180 passengers in its days as a transatlantic carrier, but is being refitted according to the men's specifications.
They want two "state rooms", with adjoining lavatories and a shower. There will also be a large sitting and dining area and, at the back, up to 16 first-class seats for guests or employees. A request for onboard internet access has also been made.
Mr Page has acknowledged that the aeroplane might seem to propel him and his business partner into the world of corporate one-upmanship. But he defended the purchase, saying the plane could be used for good causes.
"Part of the equation for this sort of machinery is to be able to take large numbers of people to places such as Africa. I think that can only be good for the world," Mr Page told the Wall Street Journal in a rare interview.
The executives have joined the club of business high-flyers who believe cars are not sufficient for getting around. Microsoft's co-founder Paul Allen owns an entire fleet of aircraft, though his flagships - two Boeing 757s - are smaller than Messrs Brin and Page's 767 model.
The two internet gurus recently pleased the charity world by emulating their chief rival Bill Gates, chairman of Microsoft, in using some of their fortune to set up a philanthropic trust for socially-minded investments that is funding projects in Africa and elsewhere.
But, perhaps inevitably, the unprecedented growth and global dominance of the internet search market by the California-based company - which was only created seven years ago - has generated suspicion that it is more like the "evil empire" than an offbeat collegiate company interested in helping the world.
The company has had a series of bust-ups with business rivals, including fighting in court with Microsoft over allegations that Google illegally poached an executive to head its Chinese operation.
Most recently, the Association of American Publishers, which includes firms such as Penguin, said it was suing Google over its decision to scan millions of books and make them accessible online - on the grounds that the company is breaching copyright agreements.
Aside from the jet, it is not clear what Mr Brin and Mr Page spent their money on. Company filings show they have both sold a considerable amount of Google's shares, which have rocketed from a flotation price of $85 a share to almost $400, valuing the company at $114bn.
Last month Mr Page pocketed about $370m from selling a chunk of shares. The two held 15 per cent of the company when it floated and, despite reducing their holdings, are still major shareholders.
The dramatic creation of wealth has propelled the duo up Forbes magazine's rich list. The latest version, published in October, showed they had jumped from 43rd to 16th place.