Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury vehicles and aircraft engines.

Rolls-Royce Limited was a British luxury car and later an aero-engine manufacturing business established in 1904 in Manchester by the partnership of Charles Rolls and Henry Royce. Building on Royce's good reputation established with his cranes, they quickly developed a reputation for superior engineering by manufacturing the "best car in the world". The business was incorporated as "Rolls-Royce Limited" in 1906, and a new factory in Derby was opened in 1908. The First World War brought the company into manufacturing aero-engines. Joint development of jet engines began in 1940, and they entered production in 1944. Rolls-Royce has since built an enduring reputation for the development and manufacturing of engines for military and commercial aircraft.