
Character mistake: The name on the sign of the pub/private members club of the Manchester United fans is spelt incorrectly: It should read "The Feisty Goat" but Feisty is misspelled on the sign as "Fiesty" instead.

Character mistake: When Mick arrives at walkabout hotel, Nugget introduces himself to Mick as if they have never met before. Yet in the first movie, Nugget is asking how Mick is getting on in New York. It may be just a case of over familiarity by Nugget but it doesn't make a lot of sense.
Suggested correction: It's quite possible that they haven't met, but Nugget's heard about Mick, e.g. from the people in the bar, stories, etc. Having no doubt heard so much about Mick, Nugget probably feels like he knows him, at least enough to ask how he's getting on.
I think it was just a scene to introduce the audience to Nugget. I'm pretty sure that if Nugget was a regular in that bar, then he must have known Mick.

Character mistake: When Carrie says to Bandit "are we doing 110? We're doing 110!" there is a shot of the Trans Am's speedometer. The needle is pointing to 110 on the kilometers per hour dial. On the miles per hour dial, the needle is pointing to a number between 65 and 70.

Character mistake: When Will finds April's lost copy of Jane Eyre, the book shop clerk reads the inscription written by April's dad and says it's a quote from the book. It's actually a quote from Bronte's poem Evening Solace.

Character mistake: When the alarms go off in the police station indicating the code 187 all the police officers are confused as to what is going on since they know nothing of MDKs. Zack Lamb should have already known what the code meant, yet he never says anything and just waits for everyone to figure it out.
Suggested correction: I took it as he went into almost shock that after so many years a murder had actually taken place. He says, "I don't believe it," indicating he knew what the code meant but then he kind of froze until Phoenix's name was mentioned.
Suggested correction: Zack Lamb is quite old and it's possible he simply forgot what the code meant. He was a pilot too, not a street cop.
When Stallone first meets Lamb after being thawed in the future, he tells Spartan he was "grounded" after the events in the opening scene so had not been a pilot for 36 years.

Character mistake: When the Smiths first enter the store Home Made, the camera pans around and faces the store's large display picture which reads, "The true measure of a home lies in it's kitchen," but the word "it's" should be "its."

Character mistake: In the final sermon, Henry says "Uncle Henry" instead of Uncle Harry - as shown in the earlier typed sermon.

Character mistake: After George reads his speech to Lucy, she says it was fine except for "the split infinitive near the end." There was no split infinitive. (For example, "to boldly go" is a split infinitive; "to go boldly" is not.) (01:29:00)
Suggested correction: She was joking. She was trying to find something to criticise in his speech because she was still angry so she made something up.

Character mistake: After the things let the dog out, Larry calls Joan and tells her that the kids let him out, and he will get him (the dog). Later, when he's downtown with the dog, he has the line about "when Joan finds out you've escaped, Conrad's out and I'm in". Where is the surprise? He already called her, so she knows!

Character mistake: When the minion tries to get out on the top of the small car, it faces forward, but two shots later, it is now facing the back.

Character mistake: The card that Speedy leaves for George to read says "Speedy Gonzalez" instead of the traditional "Speedy Gonzales."

Character mistake: On the tour boat in London, the voice on the loudspeaker says 'if you look to your right, you will see the Tower of London'. Except it's on the left, given the direction the boat is travelling. (00:53:00)

Character mistake: When Mr. Rogue is spinning the globe to assign countries to the students he spins for Albert Morio, and he puts his finger just west of North America and says "Lebanon." Lebanon is in Asia, slightly northeast of Egypt and we can see Egypt on the globe on the other side of where his finger is at. He's nowhere near Lebanon.

Character mistake: In the Air Force One scene, when lightning destroys one of the plane's engines, one of the pilots tells a co-pilot to inform Metropolis Airport that the president is on board the plane. The crew is unnecessarily repeating themselves: just a few moments before, they radioed in that "Air Force One" was on approach; the plane would only have that call sign if the president was on board.

Character mistake: When Dolph is looking at the logo for the Red Dragon brewery, he says, "That arrogant scumbag mother fucker. He put the yakuza iron claw right on the logo." But, the iron claw is not the logo of the yakuza. It's the logo of the specific syndicate run by some members of the yakuza, as Dolph stated after ripping open the shirt of that guy in the interrogation room. So, he just wrongly stated what the logo really belonged to.

Character mistake: Buster and June are watching TV, and he says, "Hey, Julie" (the actress' real name). (00:08:07)

Character mistake: When giving Eggsy a tour, Galahad tells him that Oxfords are any formal shoe with open lacing. This is incorrect as Oxfords have closed lacing.

Character mistake: Captain McCrea tells the passengers that it's the 700th anniversary of the Axiom's first flight. The Axiom has been in flight for 255,642 days. Actually, 700 years is 255,675 days. That figure includes the additional day in 175 leap years.
Suggested correction: Leap years only occur because of the earth's rotation around the sun. As the AXIOM is in space, there is no need to correct for the earth's rotation.
First, rotation is the spin of the Earth (which cause day and night). Revolution is the earth orbiting the sun (which causes years). However, this correction is not valid on the premise you're trying to present. Many films set in space still use Earth time, so a day is 24-hours, even though they're in space and there is no sunrise and sunset (although it's stated the Axiom operates on a 25-hour day). So they would use Earth's year, which takes 365.256 days. Since the Axiom isn't orbiting the Sun, it wouldn't experience a year, so they're using something else. The fact that they're slightly off suggests it's a writing mistake and there's no evidence they use an arbitrary 365.203 day year.
That's still wrong. Even if their years were strictly 365 days, 700 years would be 255,500 days, not 255,642.

Character mistake: A big deal is made about how to walk down the aisle. At home, George shows Matty it's left-together-right. Then at the church, Matty has it written on his hand, but it's right-together-left. Then Frank's assistant mentions it as right-left. But then as everybody is walking, they're strolling casually down the aisle as if in a park, with no regard to the whole issue.

Character mistake: At the end of the movie, when Jaggu is listening to the sounds recorded by PK, the audio contains the question which she asked, "Tumhare planet pe sab aise hi hote, bade kan wale?" but does not contain the answer which PK gave, even though he was sitting right there. This seems to suggest that PK did not exist in the real world.