So the Normandy invasion was unnecessary, unwanted by the Brits and it did not have any impact on the outcome of the war?

Lend-Lease came into existence with the passage of the Lend-Lease Act of 11 March 1941, which permitted the President of the United States to "sell, transfer title to, exchange, lease, lend, or otherwise dispose of, to any such government [whose defense the President deems vital to the defense of the United States] any defense article". Roosevelt approved US $1 billion in Lend-Lease aid to Britain at the end of October, 1941.

Earlier, there was an entirely separate program in 1940, the Destroyers for Bases Agreement whereby 50 USN destroyers were transferred to the Royal Navy and the Royal Canadian Navy in exchange for base rights in the Caribbean and Newfoundland.

Lend-Lease was a critical factor in the eventual success of the Allies in World War II, particularly in the early years when the United States was not directly involved [due to the protests of anti-war wimps] and the entire burden of the fighting fell on other nations, notably those of the Commonwealth and, after June 1941, the Soviet Union. Although Pearl Harbor and the Axis Declarations of War brought the US into the war in December 1941, the task of recruiting, training, equipping US forces and transporting them to war zones could not be completed immediately. Through 1942, and to a lesser extent 1943, the other Allies continued to be responsible for most of the fighting and the supply of military equipment under Lend-Lease was a significant part of their success. In 1943-44, about a fourth of all British munitions came through Lend-Lease. Aircraft comprised about one-fourth of the shipments to Britain, followed by food, land vehicles and ships.