Weapons giant Lockheed Martin agrees to buy Black Hawk maker for $8bn

Lockheed to purchase Sikorsky Aircraft, US military's largest helicopter supplier, in its biggest buy in two decades - which government will examine closely

Lockheed Martin, the largest US weapons maker, has agreed to buy United Technologies' Sikorsky Aircraft unit, the maker of Black Hawk helicopters, for more than $8bn, a source familiar with the negotiations said on Sunday.

The two companies plan to announce the deal on Monday before both report second-quarter results on Tuesday, said the source, who was not authorised to speak publicly.