German leader Adolf Hitler felt that his mobile reserves allowed him to do one major attack. Although he realised nothing could be accomplished in the Eastern Front, he still believed an offensive against the Western Allies could succeed. Hitler believed he could split the Allied forces and make the Americans and British to settle for a separate peace, independent of the Soviet Union. Success in the west would give the Germans time to design and produce more advanced weapons (such as jet aircraft, new U-boat designs and super-heavy tanks) and permit the build-up of forces in the east. Given the reduced manpower of their land forces, the Germans believed that it was better to attack in the West against the smaller Allied forces rather than against the vast Soviet armies. Even the destruction of entire Soviet armies would still have left the Soviets with more soldiers. Several senior German military officers, such as Field Marshal Walter Model did not think the attack would work. They offered different plans, but Hitler would not listen. The plan needed bad weather, including heavy fog and low-lying clouds, which would make it hard for Allied planes to fly. Hitler originally set the attack for late November, before the start of the Russian winter offensive.