Plot hole: Right after Bond escapes Blofeld and joins Tanaka and Kissy, they say they need to get to the control room (that Bond just left from). They look at the "front door" to the room, and Tanaka says, "Impossible! It's too well defended!". Why did they not go back the way Bond just came from, through Blofeld's "apartment"? Instead, they fight their way across the entire launching complex and go through another entrance, which also leads through Blofeld's apartment.
Plot hole: Towards the end of the film when Newman and the remaining stagecoach people are in the cabin at the top of the hill, Richard Boone's character sends one of his two henchman (the Anglo, not the Mexican) around to the back of the cabin to apparently surprise them from behind. Then Newman's character walks down the hill and Boone and the Mexican henchman are all killed in a shootout. Everyone comes out of the cabin, comes down the hill and the credits roll. I guess that now, almost 40 years later, that poor Anglo-henchman is still behind the cabin, waiting for them to come out.
Plot hole: When the Major and Wadislav walk up the stairs in the German mansion they are met by a pair of German officers who say something to them. Wadislav then tells the Major that he couldn't understand a word they said. What they actually said was 'Nice weather, wouldn't you agree?' Wouldn't you think that a man who speaks German well enough to convince the guards in a German HQ would understand such a simple phrase? Wadislav was chosen specifically for his ability to speak some German.