BMW, which stands for Bayerische Motoren Werke, started out by making aircraft engines.
During WWI, there was an immense need for airplane engines, especially on the German side. So a little company called Rapp Motor merged with Otto Werke, an airplane maker just up the street in Munich, combining forces to satisfy the war effort’s needs.
After World War I, German companies were banned from producing warplanes and warplane engines by terms of Treaty of Versailles. Then the company shifted to motorcycle production followed by automobiles in 1928.