When World War I started in Europe, the United States was woefully unprepared for an air war, with a mere six airplanes in its military. By the time America entered the war in April 1917, that number had increased to around 200. Obviously, it still needed more airplanes—and men to fly them. In this poster by artist Charles Livingston Bull, an American bald eagle takes on a black eagle of Germany. Bull had studied wildlife and taxidermy before the war, making this a natural subject matter for him. (Library of Congress)
Library of Congress