India, April 9 -- The weather was ideal for flying when John Walton, the son of Walmart founder who received billionaire in fortune, hopped into his small homemade aircraft in June 2005.

Unfortunately, the world's 11th richest man was found dead shortly after taking off his flight from Jackson Hole Airport in Grand Teton National Park.

While the cause of death remained unknown, Park rangers launched planned an inquiry into the tragedy. "We're sad that John Walton, who was well known and much loved in this valley, died doing something that he loved to do, which was fly aircraft," stated Grand Teton National Park representative Joan Anzelmo.

According to officials, the aircraft he was piloting when he died was a prototype ultralight plan...