Lockheed Martin is buying Black Hawk helicopter maker Sikorsky Aircraft for $9 billion (€8.3bn).
United Technologies Corp. said in June that it planned to sell Sikorsky.
Aside from Black Hawk helicopters, Sikorsky makes presidential helicopters, and also returned astronauts home after they splashed down in the Pacific Ocean at the end of their space travels.
Lockheed Martin Corp. said yesterday that it plans to add Sikorsky to its mission systems and training unit.
The deal should close by the end of the year or in 2016's first financial quarter.