Whenever an officer or enlisted man or woman of the United States Army or United States Navy or United States Air Force, detailed by the Department of the Army or the Department of the Navy or the Department of the Air Force for service with the National Guard or Naval Militia, is detailed by the Governor for special duty or requested to perform any duty involving travel not specially directed by the Department of the Army or the Department of the Navy or the Department of the Air Force, the officer or enlisted man or woman shall be allowed his or her actual traveling expenses, but no per diem.