Other mistake: During the big chase scene, a car hits a camera right after it passes a blue '68 GTO.
Other mistake: The crew goes up to Calgary in January to extinguish an oil fire, yet there's no snow on the ground, the grass is green, and all the deciduous trees have leaves.
Other mistake: In the scene where Burton and Eastwood are in the radio room, two grenades are thrown, which blow the main radio room door off the hinges and Burton and Eastwood run behind the small door and hide in that room. The German soldiers then run up and one of them throws another grenade supposedly into the radio room. However, the actor in his attempt to throw the grenade into the room instead throws the grenade into the door and it bounces back into the hallway in which he is standing and lands in front of him, yet no one reacts to this and seconds later we see an explosion as if the grenade had actually gone into the room, but it is really on the floor in front of the door and would have certainly blown the German soldiers to bits.
Other mistake: After one of Col. Kirby's soldiers has been killed he takes the dead soldier's M-16 and smashes it against a tree. Instead of a magazine the rifle has a plastic sound box, because the 'rifle' is really a toy made by Mattel.
Other mistake: When Jill tries to leave Sweetwater in the morning after Cheyenne's visit, she runs into Harmonica. He has a very nasty, coarsely stitched injury in his cheek that is not accounted for, and for which there was no time to be received, stitched, and the stitches removed again. (Special Edition DVD has a deleted scene in which Harmonica is beaten up, which explains the injury, but it is a continuity mistake within the regular movie.) (01:12:25)
Other mistake: When Walt Coogan is chasing James Ringerman on their motorcycles up the stairs, a funny slip up occurs. Ringerman makes it up OK, and Coogan follows him, only to ride headlong into the corner of the stone staircase. He is just beginning to fall over when Director Don Siegel cuts away to the next scene.
Other mistake: Taylor believes he is on a planet 300 light-years from earth for most of the movie. However, after spending months there, he would have seen the moon at night a number of times, letting him know where he really was before seeing the Statue of Liberty.
Suggested correction: Not necessarily; any astronaut knows that many, many planets have moons, so Taylor could have easily thought that it was simply an odd coincidence that the "other" planet's moon closely resembled Earth's moon.
Other mistake: 3/4 day mission to the North Pole, no-one grows a millimetre of stubble or has anything to eat.