Stewart Greene, an advertising executive whose creative acumen made airplanes sexy and indigestion entertaining, died on June 29 at his daughter’s home in Lloyd Harbor, N.Y., on Long Island. He was 91.

The cause was cardiac arrest from complications of lung cancer, his daughter, Lisa Greene, said.

Mr. Greene was a founder of Wells Rich Greene, a small agency whose commercials, seen during prime time when almost all television-watching eyes were on one of the three broadcast networks, contributed to the transformation of TV advertising in the 1960s.

He first made his mark as a creative director at the agency Jack Tinker & Partners, where he was in charge of the art department. It was there that he met Mary Wells Lawrence (then known as Mary Wells) and Dick Rich.

The three left Tinker in 1966 to start Wells Rich Greene, nabbing high-profile clients like Procter & Gamble, Samsonite, American Motors and the City of New York, for which they developed the “I Love New York” campaign. By 1971, their company was billing its clients $120 million a year (about $758 million in today’s dollars) and had become one of the top 25 advertising agencies in the country, The New York Times reported that year.