(AP) Wal-Mart heir John T. Walton, who died in the crash of his experimental, ultralight aircraft, was remembered as a friendly man who threw his considerable financial support behind efforts to educate low-income children.

Walton, of Jackson, Wyo., crashed shortly after takeoff Monday from Jackson Hole Airport in Grand Teton National Park, the company said. The cause of the crash was not known and park rangers planned an investigation, officials said. Walton was 58.

"I think all you can say is he was just a good man and today, you grieve," Jay Allen, Wal-Mart senior vice president of corporate affairs, told The Morning News of Springdale.

Walton, the middle of three sons of Wal-Mart founder and Kingfisher, Okla., native Sam Walton and a member of the company's board, was a major advocate of school vouchers, supporting efforts to create taxpayer-funded ways for students to attend private schools.

Walton founded the Children's Scholarship Fund in 1998 to provide low-income families with money to send their children to private schools. The foundation started with $67 million from the Walton Family Foundation and benefited more than 67,000 children.

In March, Forbes magazine listed John Walton as No. 11 on its list of the world's richest people with a net worth of $18.2 billion. He was tied with his younger brother, Jim, one spot behind his older brother, Rob, who is Wal-Mart chairman, and just ahead of his sister, Alice, and his mother, Helen. Wal-Mart Stores Inc. is the world's largest retailer.

"I certainly have nothing negative to say about the man at all. He was a prince," said Walton's former wife, Washington County Circuit Judge Mary Ann Gunn. "He loved to build things. He loved motorcycles. He built his own motorcycle."