Continuity mistake: The head of Mega-Maid mysteriously shrinks in size. After Spaceball-1 transforms into Mega-Maid, the head is gigantic enough for a Winnebago to fly through for a considerable length of time. However, later on in the film, after the head has been jettisoned and crashed on a beach, the head is only big enough to hold a few dozen people. This can be determined by the size of the people coming out of her nose.
Other mistake: As Dark Helmet says his line "Everybody knows that!", watch the crewman in white to Helmet's right. He starts to cover his crotch a beat too soon.
Continuity mistake: After Dark Helmet has stolen Lone Starr's ring of the Schwartz and dropped it down in the grill, Lone Starr is wearing it again after he gets into his Starship.
Deliberate mistake: There is a shot of the huge Yogurt statue that is in slow motion. You can see that the smoke from the statue is rising slower than it normally would. This was obviously done to make the shot longer for Mel Brooks' voice over to fit.
Revealing mistake: When we see Dark Helmets' hoverjeep in the desert, watch the front end: you can clearly make out the edge of the mirrored box they used for the "hover" effect.
Other mistake: When Yogurt comes out of his statue the camera zooms in and the door starts to close, but when the camera zooms out the door starts back and closes again.
Visible crew/equipment: Right after Barf and Lone Starr have stolen the two spaceballs outfits they run by a hallway with two guards in it. After the guard sees one of them and says "Nahh", look at the top of his helmet - you can see the camera and director.
Continuity mistake: In the opening crawl, the letters are capitalized normally. However, in the scene where they are fast-forwarding through it, the opening crawl is in all capital letters.
Continuity mistake: While Dark Helmet is tasting the jam that he got off the radar screen, the black man puts his hand over his mouth. But in the next shot of the black man's face his hand has disappeared.
Visible crew/equipment: After Dark Helmet drops Lone Starr's ring into the vent and Lone Starr tries to retrieve it there is a quick shot of Lone Starr getting up and backing up against the wall. If you look closely you can tell that it is a stunt double.
Audio problem: The radar operator (making the sounds of a garbled intercom) is laughing through his next line "I'm having trouble with the radar, Sir." (After/when Dark Helmet throws the intercom across the control panel). (00:21:45)
Visible crew/equipment: When our heroes enter the temple of Yogurt, there is a shot where Vespa says "Whats gonna happen now?" Behind them you can see the track the camera moves on. After the giant statue says "Silence", the track is gone. (00:45:10)
Continuity mistake: When Lone Starr and Barf watch Spaceball 1 fly away in the desert, the glare on them is red but when you see the engines of Spaceball 1, they are blue.
Continuity mistake: When Princess Vespa's Mercedes is being pulled into Spaceball one, the speed and position of the Mercedes changes.
Revealing mistake: When the "Alien" is dancing along the bar, it kicks its legs. As it dances past Barf and Lone Starr in close up, its legs are stationary and the whole model is bouncing. On cut back to its disappearance through the "stage door", its legs are kicking again. This also applies to the other animations of the "Alien." You can also see the 'stick' that it is attached to, along with the hole cut in the bar to accommodate the stick.
Revealing mistake: Before Yogurt's statue falls on Barf's foot and makes it flat, you can see that his foot is already flat.
Continuity mistake: When the people that live with Yogurt go to help Captain Lone Starr and everyone else with him in the desert, three people go to help Barf and Dot, but when it shows each group two are helping Barf and two are helping Dot.
Continuity mistake: During the scene where the princess' Mercedes is being viewed on radar, you see that the ship is headed toward Spaceball 1; however, in the next scene the princess is moving away from Spaceball 1.
Continuity mistake: In the scene where Dark Helmet is luring Princess Vespa outside, she awakens with the left strap of her wedding gown up and the right one down. However, when she steps outside, her left strap is down and her right strap is up.
Character mistake: During the scene in the diner, there is a sign that reads "EMPLOYEE'S ONLY." There shouldn't be an apostrophe.
Answer: It also might stand to reason that the very fact that Druidia has a shield is what makes it viable. It almost creates a docking port for Mega Maid who was presumably designed for that very purpose. After all, what other purpose could a space maid with a vacuum possibly have?