Laurance S. Rockefeller, 94, an early leader in venture capitalism who used his family's oil fortune to fund conservation efforts and aviation enterprises, died July 11 at his home in New York City. He had pulmonary fibrosis.

Mr. Rockefeller was a central member of one of the first families of American civic, social, economic and philanthropic life. His grandfather John D. Rockefeller founded Standard Oil and established the family tradition of giving away millions of dollars.

Laurance Rockefeller, a tall, urbane, business-minded billionaire who operated private planes and PT boats for sport, became known largely for conservation efforts. He amplified the legacy of his father -- who had created major national parks -- by expanding and preserving many of his own, from California to the U.S. Virgin Islands.

Robin W. Winks wrote in a biography of Laurance Rockefeller that his service in the late 1950s and early 1960s as chairman of the Outdoor Recreation Resources Review Commission provided the path for decades of conservation laws.

Mr. Rockefeller found great favor during Lady Bird Johnson's beautification crusade in the 1960s. In 1967, the first lady called him "America's leading conservationist."

Mr. Rockefeller also was a chief advocate for investing family money in new, often bold enterprises. Particularly fascinated by aviation, he poured money into new projects so they "would not be snuffed out by a merger because of a lack of financing."

With commercial air travel still a gamble in the late 1930s, Mr. Rockefeller gave key financial backing to Eddie Rickenbacker, the World War I ace who became chief of Eastern Airlines. Mr. Rockefeller became one of the airline's largest stockholders.

A meeting with J.S. McDonnell Jr., the St. Louis aircraft engineer and designer, led to an infusion of cash that created McDonnell Aircraft Corp., one of the most important military contractors in the aftermath of World War II.

Mr. Rockefeller was a director at McDonnell Aircraft but gradually reduced his role there to help smaller concerns, such as Reaction Motors in New Jersey, which built the Viking Rocket. He invested heavily in firms researching supersonic engineering. And one of his investment partnerships in the late 1960s, Venrock Associates, provided early funding for computer companies Intel and Apple.

"People who try to play it safe in the long run have very dull lives," Mr. Rockefeller told Forbes magazine, which listed his net worth last year at $1.5 billion.

Laurance Spelman Rockefeller, a New York native, was the fourth of John D. Rockefeller Jr. and Abby Aldrich Rockefeller's six children; he was the third son. His siblings were Abby, John D. III, Nelson, Winthrop and David.

Laurance often accompanied his father on trips to the American West, where the elder Rockefeller created Grand Teton and other national parks.

On other adventures, his role was less prominent. In summer 1929, he and Nelson were cooks and dishwashers on a shipboard expedition to Labrador led by Wilfred Grenfell.

After graduating in 1932 with a philosophy degree from Princeton University, Laurance Rockefeller attended Harvard University law school. He then inherited a seat on the New York Stock Exchange, which he rarely if ever visited.

During World War II, he served in the Navy's bureau of aeronautics as a liaison officer to aircraft production facilities on the West Coast.

After the war, he served as president of Rockefeller Brothers Inc., an investment and research organization. He also was board chairman of Rockefeller Center Inc., which oversaw one of the most prominent blocks of real estate in New York.

Conservation and recreation remained vital interests.

He sat on the boards of zoos and parks.

He created public sanctuaries in Wyoming, donating his family's property in Jackson Hole to the federal government. In 1956, he turned over half of the island of St. John in the U.S. Virgin Islands -- he owned 5,000 acres -- to the National Park Service to create Virgin Islands National Park.

He developed popular tourist resorts, including Caneel Bay on St. John and Mauna Kea Hotel in Hawaii. He operated the Woodstock Inn and the Suicide Six and Mount Tom ski areas in Vermont. Many of his properties were used by presidents and potentates, with whom Mr. Rockefeller was cordial.

He served on public commissions that developed an inventory of the nation's recreational needs and other blue-ribbon beautification panels. He often funded many of the recommendations he made.

In 1965, as coordinator of the White House Conference on Natural Beauty, he explained his mission to a public he assumed was skeptical of political leaders spending their time "talking about beauty."

"The answer is, of course, that the President, the leaders and, most significantly, the people of this country have become concerned about the kind of America our affluence is creating," he wrote in an essay published in The Washington Post. "In many ways, natural beauty is an inadequate term for this concern. . . . What is involved here is the basic quality of environment -- the health of the land and water and air on which man depends for life, as do all living things."

In 1969, President Lyndon B. Johnson awarded him the Presidential Medal of Freedom, the nation's highest civilian award.

In 1934, he married Mary French, the granddaughter of conservationist and railroad president Frederick Billings. She died in 1997.

Four of his siblings have died: Winthrop Rockefeller, who served two terms as governor of Arkansas, in 1973; Abby Rockefeller Mauze, in 1976; John D. Rockefeller III, chairman of the Rockefeller Foundation and a founder of Lincoln Center, in 1978; and Nelson A. Rockefeller, who served as governor of New York and vice president under President Gerald R. Ford, in 1979.

His nephew John D. "Jay" Rockefeller IV is a Democratic senator from West Virginia.

Survivors include four children; a brother, financier David Rockefeller, the former chief executive of Chase Manhattan Bank; eight grandchildren; and 12 great-grandchildren.

Laurance and Mary Rockefeller on their wedding day in 1934. Her grandfather was a railroad president, and his founded Standard Oil.Rockefeller, shown in 1974, liked to back ventures on the cutting edge, from aviation to computers.