An American fighter pilot who intercepts the time-displaced Enterprise in 1969 and is beamed aboard, threatening the timeline with what he has seen.
Captain John Christopher is a United States Air Force pilot sent up in a jet to investigate an unidentified object over Omaha in Tomorrow Is Yesterday. The object is the Enterprise, flung back in time to 1969, and when its tractor beam damages his aircraft, the crew beams him aboard to save his life.
Kirk at first intends to keep Christopher, but Spock discovers that the pilot's future son will lead an important Earth expedition to Saturn, so he must be returned. The crew's escape requires another time warp that restores Christopher to his plane before he ever saw the ship. He was played by Roger Perry.