Although the United States did not enter World War I until 1917, Americans were already playing a role in the fighting in Europe as members of the Lafayette Flying Corps. This brave group of Americans flew with the French. After the U.S. entered the war, many of them transferred over to the Air Service and helped train and lead the Americans who flew in Europe as part of the American Expeditionary Force. The National Museum of the United States Air Force has an outstanding collection of World War I era aircraft. Americans flew primarily French, British and Italian aircraft. German aircraft are also on display.

The U.S. Army Air Service did not become heavily involved in air combat until 1918, the last year of the war. Although the U.S. participation in the war was relatively short compared to the European Allies, it still made major contributions to victory.

The DeHavilland DH-4 (below)was a British designed observation and bomber aircraft that the United States selected to mass produce for the war effort. It became the only U.S. produced aircraft to see combat in Europe during WWI.