SAN FRANCISCO — An aircraft fleet owned by Google’s founders and former CEO received improper discounts on jet fuel that saved the three billionaires up to $5.3 million dating back to depths of the Great Recession in 2009, according to a government report released Wednesday.

The findings by NASA’s inspector general surfaced during a review of a government airfield lease for seven planes and two helicopters controlled by Google’s founders, Larry Page and Sergey Brin, and the Internet search company’s former CEO, Eric Schmidt.

The aircraft are managed through a company called H211 set up by the three men through the tremendous wealth that they have accumulated as Google Inc.’s stock price has soared from $85 in 2004 to nearly $1,100. Page, who is Google’s current CEO, and Brin, who heads the company’s special projects division, are each worth about $25 billion, according to Forbes magazine.

Schmidt, who became executive chairman after stepping down as CEO in 2011, is worth about $8 billion.

NASA’s inspector general’s report flagged the bargain that Google’s jet-setting executives got on the fuel for their flights around the world.