Three divisions were dropped: the American 82nd and 101st, and the British 6th. The British division dropped to the south and east of Sword Beach, aiming to hold the line of the Dives River. They also captured bridges over the Orne River and Caen Canal, so troops moving inland from the beaches could reinforce them. The coastal defence battery at Merville was another major target for the 6th, as it could easily fire on Sword Beach. The American divisions landed inland from Utah Beach. The 101st was to capture the causeways leading inland from the beach, secure the beach's flank along the Douve river, and secure routes further inland. The 82nd was to capture the communications hub of St Mere Eglise, and protect the beach from troops moving down the Cotentin Peninsula.

There were three, the 6th (British), and the 82nd and 101st (American)

• The British 6th Airborne had the most important mission of the three; defend the left flank of the invasion from a German armored attack. They were to land behind the beach near Caen, and the German 21st Panzer Division was near there. If the panzers hypothetically attacked and were not stopped by the 6th Airborne, they could potentially unhinge the whole left flank of the invasion area.

• The American 82nd Airborne Division was to land on the invasion's right flank and cut off German troops that would be moved down the Cotentin Peninsula to attack Utah and Omaha Beaches. They were to blow up bridges over the Merderet and Douve Rivers and occupy their banks, capturing the town of St. Mere Eglise.

• The American 101st Airborne Division was to secure four causeways behind Utah Beach to allow the invading troops to move off it. The capture of the La Barquette lock behind the beach was critical; it could be used by the Germans to flood the area and deny a timely exit from Utah Beach. They were to also link up with the 82nd Airborne Division to their right flank.

The 1st Canadian Parachute Battalion was attached to the British 6th Airborne Division for the operation.

Source:

US Army in World War II, by Rich Anderson

Three. The American 82nd and 101st Airborne Divisions, as well as the British 6th Airborne Division.