Kenneth L. Jones, 61, an Air Force officer who later worked for the Defense Department and then for a private research company, died of cancer Saturday at Fairfax Hospital.

He was born in Hudson, Colo., and joined the Army Air Corps in 1942. He was commissioned a second lieutenant and became a pilot the following year and spent the rest of the War as a flight instructor.

He Air Force sent him to the University of Colorado, where he earned a degree in aeronautical engineering in 1951. He later served in Italy and in Washington. He retired in 1965 with the rank of lieutenant colonel.

Col. Jones then became an official in the office of atomic programs in the office of the director of defense research and engineering. He later was director of analysis and programs at the defense nuclear agency. He retired a second time in 1973.

Col. Jones lived in Longwood, Fla., from 1973 to 1975 and then returned to the Washington area. He became a senior research manager for the Pacific-Sierra Research Corp., working on nuclear projects for the government. He retired for reasons of health in 1977.

He was a member of the U.S. Power Squadron and was a former vice commodore of the Chesapeake Yacht Club.

Survivors include his wife, Mildren W. Jones, of the home in Vienna; a daughter by a previous marriage, Marsha Lieberman, of Myrtle Creek, Ore.; a stepson, Lawrence N. Wright, of Fork Union, Va., and one grandson. CAPTION: Picture, KENNETH L. JONES