This is from a British Aircraft Procurement 1934-39 essay that I started (and did not finish) folllowing the recent What To Build In Place Of The Stirling Thread.
The Aircraft Industry
In April 1919 the Armstrong-Whitworth Development Company bought out Siddeley-Deasy and in May 1919 became Armstrong-Siddeley Motors Ltd a subsidiary with J. D. Siddeley as Managing Director. In 1927, Armstrong-Whitworth merged its heavy engineering interests with Vickers to form Vickers-Armstrong. At this point, J. D. Siddeley bought Armstrong-Siddeley and Armstrong-Whitworth Aircraft into his control. In 1928, Armstrong-Siddeley Holdings bought Avro from Crossley Motors. In 1935, J. D. Siddeley's interests were purchased by Tommy Sopwith owner of Hawker Aircraft and the Gloster Aircraft Company to create Hawker Siddeley. However, Armstrong-Whitworth, Avro, Gloster and Hawker carried on as separate entities competing against each other until the 1960 reorganisation, when they merged with Blackburn, De Havilland and Folland to become Hawker Siddeley Aviation.
However, in this version of history J. D. Siddeley created a new firm called Avro-Whitworth from Armstrong-Whitworth and Avro with one design team and one factory. In 1935 the new Hawker Siddeley Group created a new aviation firm called Hawker Siddeley Aviation with two divisions. The Avro-Whitworth Division under Roy Chadwick concentrated on bombers and transport aircraft. The Hawker-Gloster Division had one design team under Sydney Camm with George Carter as his deputy concentrated on fighters, but there was no rationalisation of the factories. Furthermore Blackburn, De Havilland and Folland became part of Hawker Siddeley Aviation in 1948 instead of 1960. The latter was due to a Government led rationalisation of the aviation industry, which effectively bought the real world's reorganisation of 1960 forward to 1948.
Meanwhile Vickers bought the Bristol Aeroplane Company in the late 1930s and merged its design team with their design team at Weybridge which concentrated on bombers and transport aircraft, while the Supermarine Division concentrated on fighters and flying boats. English Electric and Vickers-Armstrong merged their aviation interests in 1948, which effectively created the British Aircraft Corporation (BAC) 12 years earlier. To complete the story, BAC, Hawker Siddeley and Scottish Aviation merged by mutual consent in 1960 and nationalisation still takes place in 1977. In the real world Handley Page refused to merge and became insolvent in 1970. In this version of history it joined BAC in 1948.
The Air Ministry had Hafner's firm taken over by Westland in 1939 rather than Bristol in 1944. The Government also has Saunders Roe take over the Weir families aviation interests in 1940 instead of 1951. Both firms merge with Fairey in 1948 instead of 1960 as part of the post-war reorganisation of the industry.
The consolidation of the engine design groups was more important than the consolidation on the airframe firms. In this version of history Cosmos Engineering was taken over by Armstrong Siddeley rather than Bristol. Cosmos and Armstrong Siddeley Motors were merged to create a new company called Bristol Siddeley Engines (BSE). BSE acquired Metrovick's aero engine business (which included the F.9 Sapphire) after the war. Blackburn Engines and De Havilland Engines became part of BSE in 1948 instead of 1960. Meanwhile Rolls Royce buys Napier in 1926 instead of 1961. Rolls Royce absorbs BSE merge by mutual consent in 1960, instead of buying the company in 1966 for £63 million and that helps Rolls Royce to avoid bankruptcy in 1971.