When Ryan gets to the airport with the cardboard cutout of his sister & fiancé, you can see their heads sticking out of the top of his suitcase. But when he goes through security, there is no cardboard cutout sticking out.
When they crash the tech party, Ryan enters wearing a blue suit and then is shown partying in a blue casual shirt and khaki slacks.
At airport security, Ryan puts his laptop in a tray. He proceeds to take off his shoes and put them in a tray, but his shoes are already in the tray next to the laptop bin.
When Ryan takes a photo of Jim and Julie's cutout outside the Luxor pyramid in Las Vegas, the text and images are digitally removed from a billboard for the live "Criss Angel: BeLIEve" show that is in the shot. However, when Ryan later posts this photo up on the giant map at the rehearsal dinner, the text and images are clearly visible on the billboard.
When entering the AlphaTech party Alex is wearing a silky pink blouse, but in the next scene inside the party and is wearing a black V-Neck sweater (top). This goes along with Ryan's outfit changing (in the same two scenes) from a suit to a light blue shirt sleeve shirt and khakis.
Ryan Bingham is consistently shown swiping his credit card or American Airlines frequent flier card horizontally though the slot across the top of the American check-in kiosk to receive his boarding pass. The top slot is only to read passports on international flights. There is a card slot to the bottom right on the American kiosks to check in for flights. You cannot check in by swiping horizontally through the passport slot as Ryan Bingham does throughout the movie.
Even very frequent fliers are required to have their membership card swiped by the desk agent at the Admiral's Club. (It's the only way for AA to know how busy a given club is.) The most that would happen if they know a traveler really well is that they wouldn't ask to see their photo ID in addition to your Admiral's Club membership card.
When Ryan checks out of the Hilton, the desk clerk swipes his credit card. At hotels in the Hilton chain, the credit card is swiped at check in and the guest is simply given a bill (usually slipped under the hotel room door) on the last day of their stay. Also, since he's an HHonors member, his credit card information is probably already on file.
The movie shows Ryan going in the AA first class line, checking in at a kiosk and then being greeted by a counter agent. They do not put kiosks directly in front of the first class check-in agent. If there is one there (which is rare), it will be off to the side. Finally, the whole point of using the kiosk is to NOT talk to the person at the counter, so even if he had used the machine, he would not be greeted by anyone.
In a couple of rental car scenes, Ryan is seen handing his credit card to an attendant, and in one scene asked (as he drove off) for his #1 Club Gold Card. Hertz #1 Club Gold members generally do not have to show a credit card or their #1 Club Gold card - they just walk right to their car, get in, and go. Hertz has their credit card info on file, and when they return the car, they are simply handed their receipt - there is nothing to sign for.
When Ryan asks how many miles a round-the-world flight would cost, he's told it's 500,000 miles. On American a first class round-the-world flight costs 300,000 miles (and even less for lower classes). However, the trip is for two people, not just one.
When pictures of Ryan's sister and her fiancé's cardboard cutout are taken at sites of interest, you can see the hand of the person holding the photo. When the pictures are displayed, even Ryan's, the hand of the person holding the cardboard cutout has disappeared. However, the photos were taken using a digital camera. The clone tool and other techniques could have been used to "photoshop" the hand out.
The company Ryan works for is switching to firing people through the internet to save travel costs. Even though they can save even more money(the salaries of their own employees) by firing them as well, this particular job requires a specific skill for a specific task where not all people can learn and apply including coping with the morality issues as well, as Natalie has difficulty with.
In one scene, Ryan is upset with his assistant that his next rental car will be a Dodge Stratus. His assistant tells him he is trying for a Chrysler Sebring. Even though the Stratus and Sebring are essentially the same car, Ryan is clearly obsessed with attention to detail, such as when packing up his carry on luggage, therefore he would still prefer the Sebring.
In her presentation of the mock firing of Ned, Natalie asks him for a favor to not tell the other employees at his company because panic doesn't help anyone. Even though it is highly unlikely the employee would grant such a favor to the person letting them go, this only confirms Ryan's observation that Natalie doesn't know how people think which he states at approximately 24 minutes.
In Natalie's karaoke scene of "Time after Time", the Karaoke monitor scrolls the incorrect lyric "almost left me blind" while Natalie sings the correct lyric, "almost left behind".
When Ryan looks at his sister's RSVP wedding card, the month is spelled incorrectly "Febuary" instead of "February".
As Ryan is leaving for Las Vegas to meet Alex, the lettering of the 'American' logo above his window seat has wrinkles in it, revealing that is a decal. The livery on airliners is painted on to save weight and to prevent the aerodynamic drag that can be caused by such wrinkling, indicating the scene was shot using an out of service plane or a mock-up.
When Ryan, in his hotel room, is drying the photo having fallen into the dock, the Hilton promo sign on his bathrobe is perfectly readable in the mirror (which means the shot has been reversed).
When the yacht runs out of gas, everyone runs from the water to the beach in bare feet, carrying their shoes to keep them from getting wet. In the next scene, they disembark from a shuttle bus, on dry land, clearly having traveled some miles from the beach, yet no member of the party has put their shoes back on and they all continue to run into the hotel with bare feet, while holding their shoes, this time for no apparent reason.
When Natalie is being introduced, a slight reflection of the camera is visible as it passes the glass window of the meeting cubicle.
The scene in which Ryan is in an airport in Detroit is clearly filmed at the McNamara terminal (as can be determined by the iconic fountain and the signs for Continental at one of the B gates). However, it's made very clear in the movie that Ryan only flies on American, and American doesn't have gates at the McNamara terminal (it uses the North terminal).
When the photographer is taking a picture of the wedding party in front of the church, you can briefly see a "Maplewood Methodist Church" sign on the right hand side. Although the scene was filmed in Maplewood, Missouri, the wedding takes place at a Lutheran Church in Waupaca, Wisconsin. All other sign designations identifying the church were changed to fit the location in the film, except this one.
When Ryan is giving his second "What's in Your Backpack" talk, he is said to be in Miami, but the podium identifies a hotel in Wichita. (Not Kansas City as previously stated.)
After the rehearsal dinner, Ryan is told to turn up around 5pm for the wedding to start at 5.30pm. In February, sunset is between 5.04pm and 5.42pm for Waupaca, so it would be dark outside, however, when the wedding takes place and into the dinner itself, it is clearly light outside.
Returning from Alex's house in Chicago, Ryan is shown walking into O'Hare, checking in, then taking an underground tram to his flight. American uses Terminal 3 at O'Hare. People check-in, proceed through security, then walk to their gate, without using a tram or leaving Terminal 3.
When Ryan is meeting with his sister's soon-to-be-husband, he tells him he's "given up" his one-bedroom. Yet in the end montage we see shots of the inside of the apartment, implying he's still living there. (Actually in the original cut he did leave it and strike out and get a more homey place and become part of his surroundings in preparation for a life with Alex, but that sequence was later cut.)
Alex is upset at Ryan for showing up at her home. How would Ryan know her address unless she previously gave it to him.
Even though Natalie says she wants to be like Alex, when she's Alex's age "in about 15 years." But Alex is 34, which would make Natalie 19 when she supposedly graduated with a psych degree but the key word is "about" which by definition and in this context refers to only an approximation and not an exact number.