The 213th Aero Squadron was a Air Service, United States Army unit that fought on the Western Front during World War I. The squadron was assigned as a Day Pursuit (Fighter) Squadron as part of the 3d Pursuit Group, First United States Army. Its mission was to engage and clear enemy aircraft from the skies and provide escort to reconnaissance and bombardment squadrons over enemy territory. It also attacked enemy observation balloons, and perform close air support and tactical bombing attacks of enemy forces along the front lines. After the 1918 Armistice with Germany, the squadron returned to the United States in June 1919 and was demobilized.