Goofs

Jack watches a tape of Greg in which Greg mentions Denny and hints at Denny's drug use. However, the tape is of Greg's first night at the house. Greg didn't meet Denny until his second day at the house.

When Greg is trying to get on the plane, the flight attendant makes him wait until his row is called when there is clearly no one else waiting to board. But when Greg does board the plane, it is almost full and there are still people coming on behind him.

When Greg is in front of the TV while Jack is lecturing him about nanny cams, the flowers that Greg gave to the parents keep moving around the table.

Headrests are clearly missing in both vehicles during the race between Greg and Jack after leaving the restaurant. When they arrive at the house and everyone exits the vehicle to go inside except Greg, a wide camera shot behind the parked vehicles clearly shows a headrest on the driver's seat in the Mercedes Benz which Greg is sitting in.

When Greg is speaking with Pam for the first time in the movie, the collar of his coat is alternately up and down between shots.

Jack's deception revolves around trying to get visas for the honeymoon on Koh Samui. Americans don't need a visa to travel to Thailand. They are given 30 days visa-free on entering the country, certainly long enough for a honeymoon.

During the race every time Greg hits the brakes, you can see the tires up in smoke. This is not possible because a Mercedes S-Class has an automatic brake system.

Greg would have had to check his bag before boarding and have a tag placed on it because it did not meet the height requirement at the gate so there is no way he could bring an oversized bag on the plane.

The MA1000e alarm system has only 6 zones, so it is strange that Jack, having been at CIA, fully aware of security concerns, is content with that small an alarm system, given the size and complexity of his house (the house would require at least a GEM-1632 panel with a maximum of 32 zones but that system has a slightly but noticeably different keypad).

Greg's luggage should have a routing tag with his name and flight on it. At best it would be delayed but arrive at his location via delivery. There is no chance that someone's luggage could be delivered mistakenly to him.

At the airport, Jack uses his thumbs to take Greg's pulse. Thumbs cannot be used to take a person's pulse because your own pulse can be felt in your thumbs. Presumably both Greg and Jack would know this, but it could have been a trick to distract Greg from the signs Jack was really reading (sweat, eye contact, etc.).

Debbie Byrnes appears to have a broken nose when hit by the spiked volleyball. She ends up with a black eye, but this is a common side effect of a broken nose.

Pam mentions that Top Gun was a very popular movie when she and Kevin were dating. The movie Top Gun was released in 1986. If Kevin was Pam's fiancée, the movie does not explain how long they have been dating for. Top Gun has been a consistently popular movie ever since its original theatrical release, so she could have been referring to any point in time, really, including more recently. She never said it was when the movie was first released.

When Greg goes onto the airplane headed for Chicago, the airport is completely empty. When he is removed from the plane the waiting area is completely full of people in the terminal watching as Greg is being taken away.

All those passengers in the seated area of the airport were all the passengers on the same plane Greg was still on. They were evacuated while security dealt with him. Also, since it's 2:35 AM and the airport is empty, those people in the airport chairs are not customers who are waiting to board a different plane because the time from Greg boarding the plane from an empty airport to being dragged off is only about 5-10 minutes.

While trying to get his bag into the compartment, a man tries to push past Greg, which causes him to yell "where's the fire?" Annoyed, the passenger sits in the seat in front of him. However, when Greg is being dragged out of the plane you can clearly see the same man sitting in the seats in the terminal, as though he had been there all along.

It is assumed that as soon as Greg told off the flight attendant, she called for security and they boarded the plane and told everyone to exit the plane while they dealt with Greg.

When Jack introduces Greg to Mr. Jinx, the cat changes many times between shots (from being a fat/hairy cat to a smaller one).

Greg is practicing his marriage proposal to a patient. As the camera pans past the heart monitor, the display reads "ECG Lead Fault", which means that one of the ECG electrodes has fallen off or (more likely) that the ECG electrodes were never hooked up to the actor in the first place.

(at around 1h 30 mins) When Greg is placed on hold just before boarding, printed sheets can clearly be seen glued to the monitors.

When Jack calls his CIA contact to find out what flight Greg (Gaylord) Focker is on, he is told it leaves at 2:35, and Jack hurries off to LaGuardia Airport to intercept Greg. It is clearly night time (the Byrnes party was a dinner). But there are no flights that leave LaGuardia at 2:35 am, and it is the same night as the Byrnes party, so it couldn't have been 2:35 pm (the afternoon). Obviously, the wrong time was given to Jack Byrnes, who nonetheless was able to find Greg Focker.

When Jack is racing to the airport before Greg's plane takes off near the end of the movie, he goes from the right lane on the highway, move two lanes over and gets back to the right lane as if passing a slow-moving vehicle. But there was no vehicle in the right lane to slow him down.

Greg occasionally smokes cigarettes during the film. When he converses with Jack about Puff the Magic Dragon being about drugs, he states that puffing the magic dragon means to smoke a marijuana cigarette. Recreational use of marijuana was legalized in New York State in 2021, not in 2000 (the year the film was released).

When Greg is trying to get a plane ticket the clicking noises continue even though the ticket agent is clearly not typing.

When Greg goes to use the toilet and finds the cat in there, he turns the light on and off and the switch makes a clicking sound but the switch isn't flipped.

When Jack enters the airport a camera is clearly visible in the reflection from the sliding doors.

When Greg and Jack are racing home as the light turns green after the second light they stop at you will see in the background people watching the scene being filmed.

When Greg is on the roof he jumps down and in the window behind him, the face of a crew member can be seen looking outside.

A shadow of the camera can be seen on Pam's back after she walks by it in a bedroom.

At the end of the movie when Jack is driving to LaGuardia airport the sign above says two exit signs one is exit 7 for LaGuardia and the other is exit 8 for 111 St. For these signs to come up in this order that would mean that Jack would have to be driving from Manhattan, but in the movie he was driving from Long Island so the exit numbers should be going down.

Pam and Greg board a flight to LaGuardia Airport to meet her parents. The clip of their flight shows a 747 landing. 747s don't land at LaGuardia, and even if they did, they wouldn't be used on such short flights. The clip was shot at John F. Kennedy International Airport.

Greg buys a bottle of champagne in the Oyster Bay, NY, drug store. In New York State, champagne is not sold in drug stores, but rather in grocery stores.

It would already have been spotted during rehearsal that the cat Greg used to replace Jinx was not in fact Jinx.

There is no chance Jack would limit his MCAT record search to "Greg Focker." Focker's given name could be Gregory, Greig, Gregor or Grigor, among others. Jack would have quickly discovered that a Gaylord Focker sat for the exam in the appropriate time frame and investigated further.

When Greg jumps back in the house from the roof after setting the backyard on fire, his heel obviously breaks the window and it comes crashing down. This would have lead to an early discovery of the culprit had it been pursued.

Greg proposes to Pam during this movie. However, their wedding does not take place until the end of the sequel.

When Greg is at the drug store counter he asks if they have any nicotine patches. He is told that they don't but that they do have the gum. When the store associate takes the gum off the shelf, it is next to boxes of Nicorette patches.

Jack is a skilled former CIA agent who is a "human lie detector." His son, Denny, takes a marijuana pipe out of his coat pocket, the coat that Greg borrowed. He shows it to Jack and says "I found it in Greg's jacket pocket." Jack knows that Greg lost his luggage - and that he wasn't wearing that coat when he got there the day before (so he couldn't have had that coat with him). It seems very awkward that Jack, a skilled "lie detector" and CIA agent, believes Denny when he says that the jacket is Greg's.

Contrary to what Jack believes, it is in fact possible for cats to flush toilets with the levers shown in the film.

When Greg's MCAT scores are discussed at breakfast, Dr. Banks says "board's a killer" implying that Greg took the "boards" and did poorly. The MCAT has nothing to do with the "board" exam. The "board" exam is the USMLE or United States Medical Licensing Exam administered by the NBME or National Board of Medical Examiners and is taken in 3 parts by current and continuing medical students. The MCAT is the Medical College Aptitude Test which can be taken by anyone.

Debbie gets a swollen black eye after Greg accidentally spikes a volleyball at her and the eye heals and opens the night before her wedding. Debbie getting her eye swollen and healing all happened in the same day. It would've taken some time to heal.