Famed for its reliability the Catalina was one of the most extensively built flying-boats with around 4,000 produced. Serving throughout the Second World War and used by the 'Black Cats' the Consolidated PBY Catalina would remain in service until the 1950s.

With the Martin P3M, originally the Consolidated XPY-1 but the Glenn L Martin company won the production contract, and the Consolidated P2Y serving with the US Navy during the early 1930's, and the US Navy requiring a flying boat for patrol duties with a greater range and bigger load-carrying capability, during October 1933 both Douglas and Consolidated were contract to build competing prototypes. Only one prototype of the Douglas plane was ordered and Consolidated's XP3Y-1 was chosen to be developed.

As with the P2Y the PBY Catalina, referred to as the Model 28, had a parasol-mounted wing, but with internal bracing being introduced, and with the exception of two small struts between the hull and wing, the effect was of a wing which was virtually cantilever. The PBY had another design feature to reduce drag further, the stabilising floats could be retracted and become part of the wing. The prototype was powered by two 825-hp Pratt & Whitney R-1830-54 Twin Wasp engines, with an armament of four 0.30-in machine-guns and a bomb load of upto 2,000lb.

Flying for the first time on the 28th March 1935, the XP3Y-1 was soon with the US Navy undergoing service trails which showed that compared to other patrol flying boats currently in service Consolidated's plane showed a performance increase which was significant enough for the US Navy to want further development of the XP3Y-1 so that it could be classed as a patrol-bomber. And on the 29th June 1935 60 PBY-1s were ordered, which required 900-hp R-1830-64 engines to be installed. Designated XPBY-1, the new prototype flew on the 19th May 1936 and after its trials, in which a non-stop flight of 3,443 miles was achieved, the aircraft along with other PBY-1s, which began to be delivered during October 1936, was sent to US Navy Squadron VP-11F.

From July 1936 to December 1937 three orders were placed for PBY-2,3 & 4's. Ordered on the 25th July 1936, the PBY-2 featured minor improvements, whilst an order for PBY-3s with 1,000-hp R-1830-66 engines was placed on the 27th November 1936. The order on 18th December 1937 was for PBY-4s, which would feature the distinctive transparent blisters and 1,050-hp Twin Wasp engines.

The first PBY-4 production aircraft was sent back to Consolidated during April 1939 to be fitted with landing gear to make the aircraft amphibious. XPBY-5A, as the plane was designated, was finished in November 1939, and after testing, the US Navy ordered over 100 PBY-5As on the 25th November 1940, and these would enter service during the later part of 1941. It was also during 1941 when the US Navy adopted Consolidated's name for the plane, Catalina.

After the PBY had been in service it was felt that the Catalina would benefit from hydrodynamic improvement of the hull. Designated PBN-1 Nomad, this was the result of the research and development of the Naval Aircraft Factory. These were modified aircraft, so that production of the PBY would not be disrupted. However the PBY-6A, which was the final production version, incorporated all of the changes introduced to the PBN-1 Nomad, and was produced from April 1944.

The "Black Cats" were PBY's painted black and used to attack Japanese supply convoys at night and they proved successful in this role. It was whilst with the "Black Cats" that Lieutenant Nathan Gordon received the Congressional Medal of Honor, when on the 15th February 1944, despite under heaver fire, fifteen airmen were rescued by Lieutenant Gordan's PBY.

As with a number of American planes, such as the Grumman F4F Wildcat and the Curtiss P-40 Kittyhawk, the Consolidated PBY Catalina would serve with the RAF. With a Catalina being sent to the Marine Aircraft Experiment Establishment at Felixstowe, Suffolk during July 1939, however due to the outbreak of war trials were ended early, but an order for 50 Catalina I's was placed, these being fitted with British armament. These would enter service in the early part of 1941 with Coastal Command. One early exploit for the Catalina came when an aircraft of No. 209 Squadron found the German battleship Bismarck on the 26th May 1941, after initial surface contact was lost. It was then a Catalina of No. 240 Squadron which shadowed the Battleship until surface contact was re-established.

The PBY Catalina would also serve with the Royal Australian Air Force, Royal Canadian Air Force, USAAF (designated OA-10) and PBY-5s designated GST and powered by Mikulin M-62 radial engines would also serve with the Soviet Union. The Dutch Government also ordered PBYs for use in the Netherlands East Indies and out of 36 delivered only nine took off before capture after the Japanese invasion. An order was also placed by the French Government for 30 Catalinas during the early part of 1940, but none of these reached France before the end of French resistance.

Working alongside the Short Sunderland the Catalina made a vital contribution in the Battle of the Atlantic and it was a Catalina that sunk the final U-boat claimed by Coastal Command, which amounted to 196. As well as serving in the Atlantic PBYs would also serve in the Pacific theatre of war and play a vital role in patrolling the Indian Ocean and the Mediterranean Sea.

With a final production total of around 4,000 the Catalina, along with the Boeing B-17 Flying Fortress, would prove invaluable in the first year of the war against the Japanese due to their long range. When the war ended the flying boat versions with the US Navy were quickly phased out of service, although the PBY would be used during the Berlin Airlift (1948 – 1949), and it wasn't until the 3rd July 1957 when the last Catalina, an amphibious version, was retired.