Since the Russian invasion of Ukraine, the United States has acted in partnership with nearly 40 other governments to impose sanctions on Russia, including limits on Moscow’s access to weapons, computer chips, aircraft parts and other products needed to fuel its economy and its war. The sanctions also applied to Russian airlines including Aeroflot, its subsidiary Rossiya and others.

But despite these far-reaching sanctions, thousands of shipments of aircraft parts were successfully sent into Russia last year, according to a trove of Russian customs data obtained by The New York Times.

The data, which was compiled and analyzed by Import Genius, a U.S.-based trade data aggregator, shows that tens of millions of dollars of aircraft parts were sent to Russian airlines explicitly facing sanctions by the Biden administration, including to Rossiya Airlines, Aeroflot, Ural Airlines, S7 Airlines, Utair Aviation and Pobeda Airlines.

Those shipments were made possible by illicit networks like Mr. Patsulya’s, which have sprung up to try to bypass the restrictions by shuffling goods through a series of straw buyers, often in the Middle East and Asia.

For instance, dozens of shipments of copper wires, bolts, graphite and other parts marked as made in the United States by Boeing slipped into the warehouses of Aeroflot last year. They traversed obscure trading companies, free-trade zones and industrial parks in the United Arab Emirates and China, and then traveled into Russia, to help patch up Aeroflot’s dilapidated fleet.