The Petter family started a foundry and ironmongery business in Yeovil in the 1860s. The original founder had a number of children including twin boys who built up the family business. During The Great War Westlands built over 2,000 aircraft under licence for other companies.

Between the wars many designs were produced including the Wapiti and Lysander.

After the war, development into the helicopter market saw the company through to the late 1950s. The company was selected to become the major helicopter manufacturer in the UK.

The Lysander and Sea King helicopter are perhaps two of the major projects designed and produced at Yeovil, but Westlands were always known for producing a quality project.