John Landon is a character in the movie Planet of the Apes. He is played by Robert Gunner. Landon was a human astronaut who joined the NASA program some time in the 1960s. According to his colleague, George Taylor, Landon was an ambitious scientist who "wanted to live forever". Along with Taylor and fellow astronaut Dodge, Landon participated in a mission to test the scientific theories of Otto Hasslein regarding an object moving faster than the speed of light.
The crew of the Icarus launched out of Cape Kennedy in 1972 and spent over six months in outer space. Taylor, commander of the mission, placed the crew into a state of suspended animation, in preparation for the second leg of their journey. While they slept, the Icarus passed through a Hasslein Curve, a twist in space, that propelled the ship several centuries into the future. The ship crash-landed back on Earth in the year 3978. Splashing down into a stagnant salt lake, the crew revived and scurried to freedom.
After crash landing on the planet, Landon and his fellow astronaut George Taylor bicker as they explore the planet. Landon was an adventurer and a patriot. As such, he found it hardest of the three to come to terms with their fate and argued strongly with Taylor after their crash-landing. Taylor maintained a rigid attitude, while Dodge committed himself towards finding a means to survive on this new world. Landon meanwhile, found himself the target of Taylor's acerbic wit. Taylor laughs as Landon plants a tiny U.S. flag on the surface of the planet near the lake where they crashed.
Later, Landon and Taylor - along with another astronaut named Dodge - are captured by a group of apes and taken to a city populated by apes. During Taylor's subsequent trial, he discovers that Landon has been lobotomized by an ape scientist (which Dr. Zaius ordered) and left a mere shell of his former self. Landon is taken back to his cage, while Zaius later admits he knew Landon could talk, and had him operated on.
When John Brent visited Zira and Cornelius in Beneath the Planet of the Apes, Cornelius told him that Taylor nearly ended up a museum specimen "like his two friends", which suggests that Landon was also dead and displayed alongside Dodge by that point. It's possible that during a skirmish involving gorilla soldiers, Landon was shot and killed.