WASHINGTON/NEW YORK—The U.S. Commerce Department stepped up its crackdown against Russian airlines on Thursday, slapping Aeroflot , Azur Air, and UTair with enforcement actions for violating American export controls issued after Russia’s invasion of Ukraine. The enforcement action denies the three Russian cariers export privileges and targets the entire airlines, not just specific planes. The U.S. government believes the actions will over time make the carriers largely unable to continue flights. Previously, the United States had identified more than 170 Boeing airplanes that Russian airlines were operating in violation of U.S. sanctions, including about 40 Aeroflot Boeing 737 and 777 airplanes, 21 Azur Boeing planes and 17 UTair Boeing aircraft. The export controls bar companies around the world from providing any refueling, maintenance, repair, or spare parts or services to the identified airplanes. Deputy Commerce Secretary Don Graves said the message was clear: “Defy our export controls at your own …