Mr. MacDonald (Hari Rhodes in La Conquête de la planète des singes (1972)) was also meant to return, but after Rhodes refused, the character was changed to his brother, and Austin Stoker was cast.
This is supposedly the film that inspired Tony Mendez to create the operation "Argo" during the Iran hostage crisis from 1979 to 1981 in which he traveled to Iran in disguise as a film producer and had the hostages disguised as a film crew in order to flee the country. As such, a clip from the scene in which Caesar, MacDonald and Virgil arrive in the Forbidden City is shown in Argo (2012).
Roddy McDowall and Natalie Trundy are the only cast members to appear in four of the five original "Planet of the Apes" movies. McDowall appeared in all except the first sequel Le Secret de la planète des singes (1970), unless you include the flashback at the beginning for which he received an uncredited appearance. Natalie Trundy did not appear in the La Planète des singes (1968), but appeared in all four sequels. McDowall also starred in the television series La planète des singes (1974). William Beckley (the British newscaster on "Escape From the Planet of the Apes" (1971)) and Woodrow Parfrey (Dr. Maximus on "Planet of the Apes" (1968)) both appeared as chimpanzees on the series' pilot, and Bobby Porter (Cornelius on this film) appeared as a young chimp on two episodes (the pilot being one of them).
All five original "Planet of the Apes" movies were #1 at the U.S. box office when released. "Battle for the Planet of the Apes" spent two weeks as the #1 top grossing film: the week of June 17, 1973 it made $4,864,355 and the week of June 24, 1973 it made $4,294,934.
During the battle at Ape City, there are many scenes of tree houses exploding in flames. In reality, due to budget constraints, only one tree house was blown up. However, this explosion was filmed from multiple angles. These shots were then divided and edited into multiple places in the finished film to give the illusion that many tree houses had been blown up.