Paul Poberezny, Pilot Who Founded Popular Fly-In, Dies at 91 Paul Poberezny, who at 15 piloted the first aircraft he ever traveled in - a single-seat glider he had restored to working condition - and later founded what became one of the largest aviation organizations in the world, died on Aug. 22 in Oshkosh, Wis. He was 91. The cause was cancer, said Sean Elliott, the vice president of the Experimental Aircraft Organization, which Mr. Poberezny founded in Wisconsin in 1953 and now has more than 180,000 members. Mr. Elliott shared piloting duties with Mr. Poberezny on his final flight, a run with one of Mr. Poberezny's favorite planes, a vintage B-17 bomber, in April 2012. Mr. Poberezny, who served as a flight instructor in the Army during World War II, had a career in aviation that paralleled the rise of commercial air travel beginning in the 1950s, but that otherwise had little in common with the jet age. He preferred to build and fly planes himself, and he often said that one benefit of making forced landings in unexpected places was meeting new people. In the early 1950s, after returning to his native Wisconsin and eventually joining the Wisconsin Air National Guard - he flew a C-17 cargo plane during the Korean War - he joined an informal group of do-it-yourself airplane builders and tinkerers. In 1953 they formed the association, at first using Mr. Poberezny's basement in a Milwaukee suburb as its headquarters. The association eventually moved to Oshkosh, where it had established a popular annual "fly-in." When the first fly-in was held, in September 1953, 22 aircraft arrived. Now called EAA AirVenture, the fly-in attracts about 10,000 aircraft and more than 500,000 people. Participants, who have included celebrity pilots like Harrison Ford, often refer to the event simply as "Oshkosh." Over the years the event has included aircraft like the plane Leland D. Bryan customized in the 1950s with wings that folded in two places so that it could be flown or driven on a road. Mr. Bryan once drove the plane 40 miles and flew it 400 as he made his way to an association meeting. Experimental helicopters, antique war planes, current military aircraft and new corporate charter planes have also taken part. The association developed a lobbying arm that works with Congress and the Federal Aviation Administration to shape regulations involving experimental and small planes. "At the present the same regulations that applied to the experimental work on the Boeing 707 jet apply to us," Mr. Poberezny told The New York Times in 1959. But regulations that apply to an elephant shouldn't apply to a mouse. The association now operates a museum in Oshkosh with more than 200 planes in its collection and a recreation of a 1930s airport. Paul Howard Poberezny was born on Sept. 14, 1921, in Leavenworth, Kan. His father, Peter, emigrated from Ukraine. His survivors include his wife of 69 years, the former Audrey Ruesch; a son, Tom, who is a past president of the association; a daughter, Bonnie Parnall; two granddaughters; and a great-granddaughter. Mr. Poberezny was 17 when he first flew solo across the country, in 1939. He went on to fly hundreds of home-built airplanes, sometimes at low altitudes and slow speeds, but also aircraft like the Sabre F-86, in which he flew faster than the speed of sound. He served as the president of the Experimental Aircraft Association from 1953 to 1989. In 1999, he was inducted into the National Aviation Hall of Fame. Mr. Poberezny grew up poor in Milwaukee. He became fascinated by flight as a boy, but he did not fly in a plane himself until one of his schoolteachers gave him a damaged Waco Primary Glider. Mr. Poberezny had not been much of a student, but he was able to repair the glider quickly and figure out how to lift it into flight by towing it from the back of a car. "After that," he told The Christian Science Monitor in 1970, "they just couldn't keep me off the runway."