Force. During the winter of 1944–45, minimizing losses to flak became a priority. The 27-plane box became standard for B-17s for all of 1945, spread more laterally to avoid catastrophic damage to the formation from a single shell burst. At the same time wingmen flew more forward on element leaders, creating a box that was stacked vertically, from front to back, and laterally. This final variation presented flak gunners with a small target, produced excellent bomb patterns, and was both easy to fly and control. B-24 combat boxes B-24s of the 2nd Air Division, more difficult than B-17s to fly in formation at high altitudes and with more restricted cockpit visibility, used a variation of the 27-plane group box. One element of each squadron (normally the uppermost in the middle/lead and high/right squadrons, and lowermost in the low/left squadron) was moved to the outside of the formation so that it was abreast of the trailing element. This produced a line formation that was wide and vertically, but only deep, reducing the time over target significantly. The 96th Combat Bomb Wing further refined the formation during its bomb runs by shifting the lead squadron into the highest position, the second squadron overlapping it in trail and lower, and the third squadron in file behind the second and another 150 feet lower. This produced devastatingly accurate bombing results in the last months of the war. Fifteenth Air Force formations The Fifteenth Air Force, consisting of a preponderance of B-24 groups flying at altitudes or lower than those flown by the B-17 groups in the Eighth Air Force, employed a larger group box during the period of December 1943 to July 1944. Called the "six-box formation", it consisted of forty aircraft, with the group divided into two units of twenty B-24s, one behind the other, and each unit consisted of three squadron boxes. The center squadron (known as Able Box) of the first unit was a composite formation of six aircraft containing the group leader, with the deputy leader flying on its wing. The other four aircraft of Able Box were from the two squadrons assigned to the unit for that mission, with the six bombers formed in two vee formations in trail and stepped lower in altitude. On each side of the lead squadron were seven-bomber boxes called Baker Box (to the right) and Charlie Box (to the left), each box made