Excessive heat may have been a contributing factor in the deaths of seven puppies aboard an American Airlines plane earlier this month.
"The autopsy results, while inconclusive, stated that heat may have been a factor," spokeswoman Mary Frances Fagan said in a statement.
However, the airline believes the pups may have been in poor health prior to their flight from Tulsa, Okla., to Chicago. Five of the dogs died on board and two died later at a veterinarian's office.
Seven other dogs on the same flight were transported without incident.
The airline is defending its handling of the situation, saying the flight complied with company policy that prohibits shipping animals in hot weather.