The Consolidated Model 28, more commonly known as the PBY Catalina (US Navy designation), is a flying boat and amphibious aircraft that was produced in the 1930s and 1940s. In Canadian service it was known as the Canso. It was one of the most widely used seaplanes of World War II. Catalinas served with every branch of the United States Armed Forces and in the air forces and navies of many other nations. The last military PBYs served until the 1980s. As of 2021, 86 years after its first flight, the aircraft continues to fly as a waterbomber (or airtanker) in aerial firefighting operations in some parts of the world. No Catalinas remain in military service. The PBY was originally designed to be a patrol bomber, an aircraft with a long operational range intended to locate and attack enemy transport ships at sea in order to disrupt enemy supply lines. With a mind to a potential conflict in the Pacific Ocean, where troops would require resupply over great distances, the U.S. Navy in the 1930s invested millions of dollars in developing long-range flying boats for this purpose. Flying boats had the advantage of not requiring runways, in effect having the entire ocean available. As American dominance in the Pacific Ocean began to face competition from Japan in the 1930s, the U.S. Navy contracted Consolidated, Martin and Douglas in October 1933 to build competing prototypes for a patrol flying boat. Naval doctrine of the 1930s and 1940s used flying boats in a wide variety of roles that today are handled by multiple special-purpose aircraft. The U.S. Navy had adopted the Consolidated P2Y and Martin P3M models for this role in 1931, but both aircraft were underpowered and hampered by inadequate range and limited payloads. Consolidated and Douglas both delivered single prototypes of their new designs, the XP3Y-1 and XP3D-1, respectively. Consolidated's XP3Y-1 was an evolution of the XPY-1 design that had originally competed unsuccessfully for the P3M contract two years earlier and of the XP2Y design that the Navy had authorized for a limited production run.