Lieutenant Harold Koch Boysen was a World War I flying ace credited with five aerial victories. Boysen joined the Royal Flying Corps in June 1917. After training, he was assigned to 66 Squadron to fly a Sopwith Pup. He would not have any success until the unit re-equipped with Sopwith Camels and transferred fronts from France to northern Italy. He scored a victory in December 1917. In January 1918, he crashed while landing in a fog, and was injured. Upon recovery, he then scored four more times in May 1918, including one win shared with Lieutenant Christopher McEvoy.