Factual error: While Bridger is watching the film of the Mafia boss following Beckerman he signals for the film to be stopped so he can look at the close up shot of the man. He is watching a 16mm film shown through a bog standard projector - stop a film like that for more than two seconds without closing down the projector shutter (this doesn't happen - if it did the screen would darken instantly) and it will melt and catch fire. This doesn't happen.
Continuity mistake: Indians are on a hilltop and a jet vapour trail can be seen in the sky.
Factual error: Krakatoa is west of Java.
Continuity mistake: In the early part when Peter Fonda and Dennis Hopper are getting their choppers ready, the film clip was reversed. You can tell because the American flag on Fonda's jacket has the stars on the right shoulder, not the left like the rest of the movie. (00:06:10)
Factual error: Near the end of the film Butch is complaining about the living conditions they have to endure - jungles, swamps, snakes, night work - and Sundance sarcastically retorts "Bitch, bitch, bitch!" In 1908 the term meant just what it literally means: "Female dog." It did not adopt its current meaning of "complain" until much later. At the time the film is set - outside the context of "female dog" - it was considered to be a serious obscenity, and it would not have been used to describe something as ordinary as someone moaning about his living conditions.
Deliberate mistake: Blofeld doesn't recognize James Bond in this film, even though they met face-to-face in the previous movie, "You Only Live Twice." There is a production-related reason for this. Ian Fleming wrote "On Her Majesty's Secret Service" in 1963 (in which Bond and Blofeld met for the first time), and he wrote "You Only Live Twice" in 1964. However, "You Only Live Twice" was adapted for film first (in 1967), and "On Her Majesty's Secret Service" was adapted afterward (in 1969). Because the 1969 film was so faithful to its source material, Blofeld and Bond are basically meeting for the first time... again. The producers were aware of this continuity problem and intended to have James Bond undergo plastic surgery for "On Her Majesty's Secret Service" (which would conveniently explain Blofeld not recognizing him, as well as the fact that Sean Connery had been replaced by George Lazenby in the lead role). But the plastic surgery idea was discarded in faithfulness to the novel, resulting in a glaring continuity problem between the 1967 and 1969 films.
Continuity mistake: It is 1940. Two pilots come out of a house - one of them has just lost his wife and family in the London Blitz, the other is an RAF Squadron Leader. The door they come out of has a modern electric bell push - a post 1965 version, white rectangular box with a round button.
Continuity mistake: During the infamous scene where Barbara Windsor loses her bikini top, Hattie Jacques is shown several times, but her hat disappears in one shot, reappearing in the next, and so on.
Revealing mistake: When McCullough is discussing Prudy's oddities with the matronly lady out front of the mayor's house, it is obvious that the lady is standing on a dirt-covered concrete sidewalk.
Factual error: At the end of the 'Goodbye' the men all board a train which leaves along a track on a seaside pier. The shot changes from this stylised vision to a shot of an Edwardian Lady alone on a railway platform. In the background is a 1970s, ie. modern, diesel train.
Visible crew/equipment: In the last scene, when they are riding alongside a river, shortly after the harmonica player changes songs, there's a closeup of John Wayne and appearing from the right on the other side of the river, a pickup truck appears, and then they quickly cut to different characters. (01:56:55)
Visible crew/equipment: In several scenes there are rectangular arrays of studio lamps visible, reflected in the actors' space helmets.
Visible crew/equipment: When Woody Allen cuts out a piece of glass out of a shop window, the camera, dolly, some crew members and a crowd of spectators can be seen reflected in the glass.
Revealing mistake: Early in the film Gene Hackman tests a rocket-powered backpack outside the space station. He slowly spins sideways through a complete circle, but instead of each side of his body being lit up in turn as it's pointed towards the sun, the light stays constant throughout the maneuver, showing that the makers just took a photo of Hackman and rotated it.
Continuity mistake: Gladstone has a drink in Dr Nookey's office, but he doesn't pour it. It just appears in his hand.
Revealing mistake: Sam is supposedly far away from civilization, but throughout the movie you can see a ski slope in the background. (00:16:05)
Factual error: In the 19th Street Parade, it shows the Budweiser Clydesdales pulling their famous wagon. Even though this movie is set in 1897, Budweiser did not start using Clydesdales until April 1933 when the sons gave their father, August Busch Sr., the owner of Budweiser, a 6 team team of Clydesdales to celebrate the end of Prohibition.
Continuity mistake: Sykes is shot in the right leg, in the thigh area, by the bounty hunters. We see the blood clearly on it when he sits on a rock and holds his leg. Later, when he returns to Aquaverde where he meets Robert Ryan, we see as he sits on his horse that his left leg is bandaged.
Continuity mistake: At the dinner scene when Mattie Ross is trying to obtain Rooster Cogburn's services, Rooster clears the table, and in the next scene he re-clears the table by pushing everything aside to play cards with Chin Lee.
Factual error: As director Ronald Neame himself points out in his commentary to the DVD, immediately after Sandy has been heating a piece of bread in the fireplace, she grabs the end of the fork on which it is placed and does not burn herself. (00:19:00)