By Jonathan Davies

Fighter jet manufacturer Lockheed Martin is set to buy helicopter maker Sikorsky in a deal worth $9 billion (£5.78bn).

It will be the biggest purchase made by Lockheed, which is overseeing the development of the F-35 fighter jets for the US Air Force, since 1995.

Sikorsky, which is owned by United Technologies, is largely famous for the Black Hawk helicopter used by the US military since the 1970s. It also makes the Sea King, which has also been manufactured in the UK under license for the British military.

United Technologies last month revealed its intentions to sell Sikorsky, and says it will return money to investors by buying back shares.