It served with Eighth Air Force in England, from April 1944 until the end of the war, converting from the Consolidated B-24 Liberator to the Boeing B-17 Flying Fortress in the middle of combat operations.

[7] After the Pearl Harbor attack the group began antisubmarine patrols off the Northeast coast of the United States, but soon became part of Western Defense Command and moved to Pendleton Field, Oregon.

[9] The 34th provided cadres for a number of heavy bomber groups that served with Eighth Air Force during this period.

[10] The group helped to prepare for Operation Overlord, the invasion of Normandy, by bombing airfields in France and Germany, and supported the June landings by attacking coastal defenses and communications.

It supported ground forces at Saint-Lô in late July and struck V-1 flying bomb launch sites, gun emplacements, and supply lines throughout the summer of 1944.

Targets included marshalling yards in Ludwigshafen, Hamm, Osnabrück, and Darmstadt; oil centers in Bielefeld, Merseburg, Hamburg, and Misburg; factories in Berlin, Dalteln, and Hanover; and airfields in Münster, Neumünster, and Frankfurt.

[10] After V-E Day the group flew six missions carrying food to flooded areas of the Netherlands and transported prisoners of war from German camps to Allied centers.

[7] The 34th Tactical Group was activated in July 1963 to train Republic of Vietnam Air Force (VNAF) personnel in counter-insurgency operations.

[15] The squadron's forward air controllers became more critical as the war expanded into populated areas and it became necessary to minimize civilian casualties.

These incidents confirmed the plan to convert the squadron's attack aircraft to the Douglas A-1 Skyraider[17] The 34th also flew combat missions, including close air support, fighter escort and interdiction, psychological warfare, aerial supply, forward air control and tactical liaison.

Prior to the passage of the Gulf of Tonkin Resolution, the United States had interpreted the Geneva Accords as prohibiting jet combat aircraft from former French Indochina.

[18] On the night of 1 November, Viet Cong located just outside the perimeter of Bien Hoa attacked the base with mortars, destroying five B-57s and damaging an additional 15.

[19] Aircrews of the 1st Air Commando Squadron performed the first combat tests of the FC-47 (later Douglas AC-47 Spooky) gunship beginning in December 1964.

As more Air Force units moved to Bien Hoa,[20] the 6251st Tactical Fighter Wing replaced the group in July 1965, and the 34th was inactivated.

This article incorporates public domain material from the Air Force Historical Research Agency "34th Bomb Group Mission Summary: May–August 1944".