Mission Chicago was the 27th serial of the airborne assault, and was flown by the troop carrier
C-47 Skytrains of the 434th Troop Carrier Group at
RAF Aldermaston. 52 aircraft acted as tugs for an equal number of
CG-4A Waco gliders carrying 155 troops, a
Clark CA1 bulldozer, sixteen
57-mm (6-pounder) antitank guns, and 25 small vehicles. 2.5 tons of ammunition and 11 tons of equipment were also transported, including an
SCR-499 radio set for the division headquarters command post. Chicago was primarily an artillery reinforcement mission. Aboard 44 gliders were Batteries A and B of the 81st Airborne Antiaircraft Battalion - both batteries were antitank batteries and equipped with the 57-mm (6-pounder) antitank guns. The other 8 gliders carried small elements of the
326th Airborne Engineer Battalion, the 101st Signal Company, the antitank platoon of the
327th Glider Infantry Regiment (GIR), and a
surgical team of the 326th Airborne Medical Company. Also accompanying the glider serial in a last-minute change was the assistant division commander (ADC) of the 101st Airborne Division,
Brigadier General Don Pratt, who had been designated to command the seaborne echelon. The mission had originally been planned for glider release at
civil twilight on the evening before the amphibious landings, but to protect the gliders from ground fire the time was changed on May 27 to 04:00 on D-Day, 2 hours before dawn. The designated destination in France was Landing Zone (LZ) E, an area co-located with and slightly overlapping one of the paratroop drop zones, DZ C. The area was chosen as central to the operations of the division and because a BUPS beacon ("Beacon, Ultra Portable
S-band") was to be in place there on which the serial commander could guide using the SCR-717 search radars installed in the aircraft of flight leaders. The landing zone was a triangle-shaped area a mile in width at its mile-long base along the road connecting les Forges (a hamlet south of
Sainte-Mère-Église) and
Sainte-Marie-du-Mont. The zone was in depth and its eastern edge ran through Hiesville, the division
command post two miles (3 km) west of Ste. Marie-du-Mont. In addition to its central locality, the fields within the zone were on average twice the length of most others in the vicinity. Many of the fields, however, were bordered by trees in height and not
hedgerows, a fact that did not show up well on aerial reconnaissance photographs. ==Glider assault==