The Boeing B-17 Flying Fortress and the Consolidated B-24 Liberator were two of World War II’s top US heavy bombers. They are easily counted among the top bombers of World War II and played large roles in determining the cause of the war. The United States produced far more military aircraft in WWII than any other power. Not only that, but the US also placed more emphasis on producing far more bombers and other more expensive and complicated aircraft than any other nation.