It is the largest bomb squadron in the Air Force.

Four heavy bomb squadrons were constituted 16 May 1942, and assigned to the group.

The ground support members of a bomb squadron numbered 15-20 officers and 250 to 300 enlisted men.

Established as a very heavy bomb squadron in 1942.

A month later, the 366th also gained the 34th Bomb Squadron.

The other two bomb squadrons regained tactical status on 5 September 1963.

The unit was formed with three reassigned bomb squadrons (402d, 411th and 430th).

The unit was formed with three reassigned bomb squadrons (21st, 41st and 485th).

The 91st had six B-17s shot down, all from the 401st Bomb Squadron.

The unit was formed with four bomb squadrons (873d, 874th, 875th and 876th), all being newly-constituted.