The unit was reactivated and elevated to Wing status in 1952 as a SAC B-47 Stratojet organization until the phaseout of the aircraft in 1964.

[1] The unit's operational squadrons (29th, 44th and 45th) were equipped with Douglas B-18 Bolos[2] then early Boeing B-17 Flying Fortresses and Martin B-26 Marauder aircraft to train, and patrol the Caribbean area, later to provide air defense of the Panama Canal after the Japanese attack on Pearl Harbor.

In March 1944, the group left the United States and deployed to a former B-24 Liberator airfield at Chakulia, India.

The cause was traced to the fact that the B-29's R-3350 engine had not been designed to operate at ground temperatures higher than 115 °F (46 °C), which were typically exceeded in India.

However, all the supplies of fuel, bombs, and spares needed to support the forward bases in China had to be flown in from India over "The Hump" (the name given by Allied pilots to the eastern end of the Himalayan Mountains), since Japanese control of the seas around the Chinese coast made seaborne supply of China impossible.

The Hump route was so dangerous and difficult that each time a B-29 flew from India to China it was counted as a combat mission, The first combat mission by the group took place on 5 June 1944 when the group's squadrons took off from India to attack the Makasan railroad yards at Bangkok, Thailand.

On 15 June the group participated in the first Army Air Forces attack on the Japanese Home Islands since the Doolittle raid in 1942 when it took part in the bombing of Yawata.

Operating from bases in India, and at times staging through fields in China, the group struck such targets as transportation centers, naval installations, iron works, and aircraft plants in Burma, Thailand, China, Japan, Indonesia, and Formosa, receiving a Distinguished Unit Citation for bombing iron and steel works at Yawata, Japan, on 20 August 1944.

The 40th made daylight attacks from high altitude on strategic targets, participated in incendiary raids on urban areas, and dropped mines in Japanese shipping lanes.

Received a Distinguished Unit Citation for attacking naval aircraft factories at Kure, oil storage facilities at Oshima, and the industrial area of Nagoya, in May 1945.

After V-J Day, the group dropped food and supplies to Allied prisoners in Japan, Korea, and Formosa, and took part in show-of-force missions.

The unit was reactivated as the 40th Bombardment Wing, Medium at Smoky Hill Air Force Base, Kansas on 28 May 1952.

Flew second-line Boeing B-29 Superfortresses in 1953–1954 which had returned from Kadena AB, Okinawa and the Korean War while becoming operational.

This article incorporates public domain material from the Air Force Historical Research Agency