A Lun-class ekranoplan, one of the Soviet aircraft that inspired Rutan's project.

Renowned aircraft engineer and designer Burt Rutan, who officially retired in April 2011, reveals exclusively to Popular Mechanics today that he has devised "a new concept for a seaplane that may allow for operation from any surface: water, snow, grass, and hard surface."

Reports proliferated in late 2011 that the 69-year-old founder of the innovative aerospace research firm Scaled Composites was working on a seaplane that he could use to go lake-hopping near his new home in Coeur d’Alene, Idaho. Rutan said at the time that his design was inspired by Cold War–era Russian craft like the MD-160 Lun-class ekranoplan. "It is a combination wing ship and seaplane," he said at a meeting of the Experimental Aviation Association.

But Rutan tells PM he has abandoned his initial concept and design and is now working on an entirely new type of aircraft. For now, he declined to provide details of the design and says he won’t be satisfied that he has broken new ground until the new craft is operational. "I will call it a ‘real breakthrough’ only if it flies like I think it might," he says.