Lieutenant John Knox MacArthur (14 January 1891 – 9 August 1918) was an American World War I flying ace credited with six aerial victories.

[3] MacArthur was an electrical engineer before he joined the U.S. Army Air Force.

[1] Having scored all of his victories in the Nieuport 28, he was one of the most successful pilots in the type, along with Douglas Campbell.

Outnumbered and handicapped by his presence far behind the German lines, Second Lieutenant MacArthur and three flying companions fought brilliantly a large group of enemy planes, bringing down or putting to flight all in the attacking party, while performing an important mission.

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