Visible crew/equipment: In the scenes where Sloan, Cameron and Ferris are driving to Chicago for the first time in the Ferrari, there is a brief shot of the Ferrari passing a car on a bridge. Look in the bottom right hand of the screen, a perfect shadow of a person on the road. (Original VHS version, it has been taken out of the recent TV versions).
Visible crew/equipment: At the very end when the credits are rolling but the movie continues, Rooney boards a school bus. When a student hands him a gummy bear, a mike is visible in the upper left of the screen. This was a TV version of the movie.
Continuity mistake: Near the very end, Ferris races home in vain as both Jeanie and his parents beat him home. Ferris is still in the kitchen as we see his parents at the base of the stairs, saying 'Let's go check on him.' They turn and start up the stairs. The next shot shows Ferris racing up the stairs. Next, we see the parents begin to mount the staircase (this time from a different angle) for a second time.
Factual error: The odometer only goes up by 10 miles between the time Cameron freaks out and when they're back in the garage, but they stop at a famous Chicago lighthouse when Cameron freaks out that actually is 1/2 hour outside the city.
Continuity mistake: When Ferris Cameron and Sloane are driving into Chicago they're speeding and flying by every car, but in one shot you can see a car pass the Ferrari in the background. It happens soon after they go airborne and you can hear the Ferrari's engine roaring as the other car passes them by.
Visible crew/equipment: When Jeanie pulls up to the field in her car and she says "I hate him." You can see the reflection of the boom mic and the camera in her slightly rolled up window. (00:50:30)
Continuity mistake: In the opening scene where Ferris is seen lying in bed he is facing his bedroom door. His mother moves him onto his back. When his sister comes into the room, there is one shot of him magically on his side again. In the next shot when he says, "Jeanie!" he has returned to his back almost instantly.
Continuity mistake: When Rooney is at the Bueller house, he slips off the water spout into mud. His shoe is stuck in the mud when he pulls his foot out. Yet, there is no mud on his calf, which was also in the mud.
Continuity mistake: When the flower deliveryman goes to leave the Bueller house, he toots the horn before speeding off after Rooney flips him the bird. It then cuts to a wide shot of the front of the house and the van is gone. We never hear the van's tires clearing the bump between the driveway and the road, and the van would've had to be going excessively fast to have cleared the driveway in the time between hearing it set off and the wide shot.
Continuity mistake: If you look closely every time a clock is shown you can tell they do not match up. The times match up at the beginning but then proceed to jump back and forth throughout the movie.