Beginning in March 1944, they bombed rail road and highway bridges, oil tanks, and missile sites in preparation for the invasion of Normandy.

Between October and December 1944, they bombed bridges, road junctions, and ordnance depots in support of the assault on the Siegfried Line.

On 16 December 1944, during a period of poor flying weather, the Germans launched a major offensive, known as the Battle of the Bulge, in the Ardennes Forest.

When the weather cleared, 99th BW units bombed supply points, communication centres, bridges, marshalling yards, roads, and oil storage tanks.

[2][4] Performed bombing operations in Europe until V-E Day This unit earned the following organizational service streamers: This article incorporates public domain material from the Air Force Historical Research Agency