Continuity mistake: As the two look-outs get on the big wheel the thin guy with the ventriloquist's dummy sits on the right. But later in the film he is on the left.
Continuity mistake: During the scene when Wally gets hit by the soldier in the cafe, and Wally bumps into another soldier, causing him to go into a cake, take notice of how much cake is on him throughout the different camera shots. Also Pops (the owner) starts to wipe the cake off of the soldier's face. The amount of cake changes between shots. (00:09:20 - 00:10:15)
Continuity mistake: When the Army knocks a hole into the front door of the Douglas home with the anti-aircraft gun barrel, notice that the position of the hole changes between shots. And when the soldiers pick the door off of Mrs. Douglas you do not see the hole. Also notice that the door is standing back up and intact, in the background, as the soldier explains to the Douglas family about the gun. (00:29:30)
Continuity mistake: When Ward's tank rampages through his home's front door, strangely enough there are two exact angles of it, one right after the other. On the first, the door falls down, but the next time it's dragged several meters ahead.
Continuity mistake: When Captain Loomis shows up in Barstow, he gets out of the vehicle and its lights are on. When he's standing in front of the car and we see him from behind, the lights are off. They are then on again when he gets fired on.
Continuity mistake: After Sitarski hands Donna her doughnut there's a close-up of both his hands over the counter, yet a frame later, from a different angle, his right arm is on Donna's back.
Continuity mistake: Inside the plane, when Donna tells Loomis that she can't have sex, he backs out, yet a frame later he's on top of her again.
Continuity mistake: Before the dance contest Donna paints her lips next to a Dumbo sign. The white paper coming out of her bag disappears in the side shot.
Continuity mistake: When the security bar is placed on the guys sitting on the ferris wheel, the rifle appears on the back shots, but disappears on the front ones.
Continuity mistake: In the barn with Ward, who is covered in dust, Wood presses the gas pedal and Ward's head bends backwards for a brief second. In that angle, his head is spotless, only to return back to dusty in the following shots.
Continuity mistake: When Ward is about to nail the crown on the front door, his hand is facing right. A frame later it faces upwards.
Continuity mistake: When the Douglas' home is sliding down the cliff, it has moved a long distance seen from sea level view, but very short from Ward's POV.
Continuity mistake: After Ward enters the barn in reverse gear and comes to a stop, he is spotless, yet from a front shot, a frame later, he is covered in white dust.
Continuity mistake: When Ward turns the cannon and destroys the stuff in his home, the mess differs between shots, with stuff fixing itself and relocating somewhere else.
Continuity mistake: When the Douglas kids's bedroom plummets, the kid on the left is facing left, yet in the close-up he is facing the right.
Continuity mistake: After Kelso releases the sidecar's screw he makes a quick right turn, yet a frame later, from the wide angle, the handlebar and the bike are both facing straight.
Continuity mistake: When Kelso drives Sitarski in his sidecar, his white scarf swaps from over his chest to over his shoulder, back and forth.
Continuity mistake: When Kelso faints on the street a plastic Santa Claus falls on him, feet over Kelso's head. However, in the close-up, the Santa has turned 180º. Two seconds later, when the soldiers come to rescue him, Kelso and Santa have turned 45º to the right.
Continuity mistake: Kelso's plane has flames all around which suddenly disappear when the plane arrives downtown (and, most probably, different plane models and sets are used).
Continuity mistake: Kelso's plane crashes against a streetlight which hangs next to the cockpit, but it disappears in further shots.