Despite being designed in the early 1930s, with its first flight in 1935, the Catalina was the most-produced amphibian of the Second World War. It entered service with the US Navy in 1936 in limited numbers, with the early types being pure flying boats without wheels. The introduction of the PBY-5 in 1939, with retractable wheels, led to the largest US Navy aircraft order since the end of the First World War. The integral undercarriage made the type much more versatile.a potential war in the Pacific, this was a valuable advantage, and Consolidated had to double the size of its production line to cope with demand.
