Constituted as 394th Bombardment Group (Medium) on 15 Feb 1943. Activated on 5 Mar 1943. Trained with B-26's. Moved to RAF Boreham England, Feb-Mar 1944, and assigned to Ninth Air Force. Their group marking was a white diagonal band across the fin and rudder. When the first Martin B-26 Marauders of the Group arrived some hardstands and buildings were still being built. Operations commenced only 12 days after the majority of the group arrived with the initial mission being flown on 23 March.
In the weeks that followed, the 394th was repeatedly sent to attack bridges in occupied France and the Low Countries, which led to its dubbing itself 'The Bridge Busters'. A total of 96 missions, on which 5,453 tons of bombs were dropped, were flown from Boreham before the 394th was moved on 24 July to RAF Holmsley South in the New Forest due to the urgent requirement of IX Bomber Command to extend the radius of action of part of its Martin B-26 Marauder force.
There was no break in operations at this critical period when the St Lo offensive was underway. The 394th received a Distinguished Unit Citation for its work during the period August 7 to 9, when it made a series of attacks against heavily-defended targets, destroying four rail bridges and devastating an ammunition dump.
It was during a bridge attack on 9 August that the Lead B-26. piloted by Captain Darrell Lindsey, was hit by flak and the right engine set alight. Although knowing that the fuel tanks were likely to catch fire and explode, Lindsey did not waver from leading the bomb run or order his crew to bail out until after bombs had been released. The bombardier offered to lower the nosewheel so that Lindsey might escape through the nose hatch but, knowing the likelihood of his losing control if this was done, Lindsey ordered the bombardier to jump. Lindsey did not escape before the aircraft crashed.
The award of a posthumous Medal of Honor was the only occasion that this highest US award for bravery went to a Ninth Air Force bomber crewman living in the ETO. All told, six 394th B-26s were lost in operations from Holmsley South. The group's aircraft began to move to the airfield at Tour-en-Bessin in France (A-13) on 21 August and the last personnel left Holmesley South on the 31st.
On the continent the group hit strong points at Brest and then began to operate against targets in Germany. Took part in the Battle of the Bulge, Dec 1944-Jan 1945, by hitting communications to deprive the enemy of supplies and reinforcements. Bombed transportation, storage facilities, and other objectives until the war ended; also dropped propaganda leaflets.
By VE-Day, the 394th was based at Venlo (Y-55) in the southeastern Netherlands. The group remained in the theater to serve with United States Air Forces in Europe as part of the army of occupation at Kitzingen, Germany. It was transferred, without personnel and equipment, to the United States on 15 February 1946 and was inactivated on 31 March 1946.