Not only that, but Germany was suffering a shortage of materials needed to build the aeroplanes. Things got worse for the Germans when the USA joined the war in December 1941, because the Americans brought bombers to the United Kingdom, and they attacked Germany from there. Soon, hundreds of American and British bombers were attacking Germany every day and night. The Luftwaffe was unable to stop British and American planes from attacking German aircraft factories and other industrial targets in large numbers at night.