Frederick Joseph Christensen Jr. (October 17, 1921 – April 4, 2006) was an American fighter pilot and flying ace who flew with the United States Army Air Forces during World War II. A member of the 56th Fighter Group in England, Christensen scored 21½ aerial victories. He later served 24 years as a command officer with both the Air National Guard and the Air Force Reserve, retiring as a lieutenant colonel.