At the end of World War II, wanting to equip their aircraft carrier strike forces with the new superpower weapon, the atomic bomb, the US Navy formulated a requirement for a new bomber that could take off directly from an aircraft carrier's deck, carrying nuclear weapons.
At first, this was considered impossible due to the large size of the bomb for a typical carrier aircraft, but in 1947 the Mark 4 bomb appeared, which could potentially fit into the bomb bay of a twin-engined bomber. In the same year, North American, which during World War II produced such well-known aircraft as the B-25 Mitchell bomber, Texan trainer and the most famous American fighter, the Mustang, proposed the concept of a deck-based aircraft with two piston engines, supplemented with a jet engine to accelerate takeoff from the aircraft carrier deck and to improve performance in emergency flight situations.
The maximum size of the aircraft would be critical in carrier deck operations, so it had to have not only a wing folding mechanism but also a tailfin which could likewise be folded when moved into the carrier's hangar deck. In addition, it was possible to load not only nuclear but also conventional weapons.
On July 3, 1948, the first flight of the prototype took place, now designated the XAJ-1 Savage. The plane turned out to be very large indeed and it became the largest and heaviest aircraft so far to be based on aircraft carriers. The bomber had a three-man crew, and to increase the flight range additional fuel tanks were installed at the ends of the wings.
The auxiliary jet engine was located in the lower middle part of the fuselage, and the undercarriage was reinforced due to the significant weight of the aircraft and for additional safety when equipped with nuclear weapons. Tests of the aircraft lasted until 1949, after which North American received orders for 140 aircraft in addition to the three prototypes already built. Series production began in 1949, and the first 47 aircraft built received the AJ-1 designation. In the spring of 1950, the first AJ-1 was delivered to the aircraft carrier USS Coral Sea (CV43).
The first few months of the AJ-1's service on carriers were marked by a number of incidents, mainly during takeoff and landing. The plane was quite tricky to pilot and demanded maximum attention from the crew, and since the standard armament was primarily nuclear weapons, the responsibility of the crew was multiplied. To prevent possible unwanted consequences, the Navy decided to temporarily remove the atomic bombs from the AJ-1 and focus on training flights, while the aircraft were converted to carry conventional TNT bombs. Nuclear weapons as standard were returned to the AJ-1 only in 1952, when the probability of fatal incidents was reduced to an absolute minimum.
At this time, North American had already made a number of changes to the design of the aircraft and began production of the more advanced AJ-2, which gradually began to replace the AJ-1 in aircraft carrier groups. At the same time, it was decided not to retire the AJ-1 from service, but to convert them to a standard that was called AJ-1 (Retrofitted), which was generally similar to the AJ-2.
After the beginning of the Korean conflict, several aircraft carriers equipped with the AJ-1 were sent to the Southeast Asian region, but no decision was made to use nuclear-armed aircraft. The operational service of these aircraft lasted until the mid-1950s, after which they were transferred to ground-based training units or converted into tankers for inflight refueling.