Terrence Ing, 29, claims airline employees refused to provide a veterinarian and other care after the dog became sick. He is seeking unspecified damages.
Tim Smith, a spokesman for American Airlines, a unit of AMR Corp. (AMR), declined to comment on the allegations but defended the company's pet transport practices.
According to the suit, Ing flew 2-year-old Willie from New York to San Francisco on Aug. 2. When Ing went to retrieve him, the dog did not come when he was called, said Ing's attorney, Corey Evans.
Employees said a veterinarian would arrive in five minutes, but one was never called, the suit alleges.
Workers then took Willie to a hangar off limits to Ing, who did not see the dog for another five hours, the suit says. By then the dog was dead.
It was unclear why Willie died, Evans said. Animal paramedics said the dog may have survived had employees provided adequate care, the suit said.