LOUISVILLE, Ky. — An Iranian national and an American citizen who worked as an airline pilot pleaded guilty Monday to charges they plotted to ship helicopters and aircraft parts for Iran’s state-run civilian airline, in violation of the US trade embargo.

Their scheme, hatched in 2007 and continued until 2011, was foiled before the defendants arranged any deliveries, federal authorities said. The men had hoped to make millions by selling the parts to Iran Air, which is owned by the country’s government, authorities said.