When Thornhill is writing the message on the matchbook, the message takes up three lines and reads "They're onto / you - I'm in / your room." When Eve opens the matchbook below, the message takes up four lines and reads "They're on to / you / I'm in your / room." The matches also change from being half full to totally full.
Thornhill complains that he only has one suit for his stay in Chicago, yet when he heads out into the prairie he has a different colored suit on. Director Alfred Hitchcock claimed that it was actually the same suit that just looked a different color due to film color-matching techniques. However, according to Eva Marie Saint, Cary Grant loved clothes and didn't want to see the blue suit from the hotel scene in Chicago trashed from crawling round in the dirt to avoid the crop duster. So, a different suit was used for that scene (which happened to be a different color).
Thornhill is taken from Mt. Rushmore in an ambulance with a hatchback-style rear gate, which is the correct rear door for an ambulance conversion of a station wagon. When he arrives in the forest to meet Eve, he emerges from a station wagon with a standard lower tailgate and upper hatch - not an ambulance.
At the very beginning of the film, Thornhill is seen walking down a crowded New York City sidewalk. Some of the people walking in front of him also appear walking behind him.
In "George Kaplan's" room at the Plaza Hotel, we see a close-up shot of Thornhill pressing the call button for the maid. Visible in this shot is a telephone with a coiled cord. But in all other shots that show that phone, it has a straight, non-coiled cord.
When the Mercedes carrying Roger is balanced on the rocky cliff, the left rear wheel is spinning in the air. Moments later, the car drives back on to the road. In a rear wheel drive car from the 1950's, all of the torque would be delivered to the free wheel, making it impossible for the car to move without being pushed or pulled.
In the crop dusting sequence which allegedly takes place in northern Indiana the highway 41 sign is square which is incorrect. Highway 41 is in fact a U.S. highway which has a completely different shaped sign. Only the secondary state highways have square signs.
When the crop duster is assailing Thornhill, the bullets hit the ground after the plane has passed. In strafing, even more so in a slow-flying biplane, the bullets would arrive at the target well before the plane passed.
When Roger tries to purchase a train ticket in New York, he finds there aren't any rooms left. The ticket agent then says he'll just have to go coach. New York Central's 20th Century Limited was all-Pulllman; no coaches.
When Roger is shown to be looking at the floor indicator of the lift in the hotel to see which floor Eve is going to, because of the angle, it would have been impossible for him to see the indicator where he was standing at the desk.
The line "our friend who's assembling the General Assembly" is a deliberate play on words, and it's in the script. It is not a case of Thornhill (or actor Cary Grant) erroneously saying "assembling" instead of "addressing".
It has been argued that after the UN killing Thornhill is fleeing aimlessly and that nobody, not even he himself knows where he's going to end up so how could Vandamm and his team have known to plant their agent - Eve - to meet him on the train at Grand Central. The answer is that Van Damm and co did the same thing that Roger did; as Roger explains on the phone to his mother, Roger called Kaplan's hotel and found out Kaplan was headed for another hotel in Chicago. So Roger heads to Grand Central to catch a train and in the meantime, Van Damm has done the same assuming that that is where Roger who he thinks is Kaplan will be headed.
When the pre-Columbian figure breaks on Mt Rushmore, it contains 35mm film, not microfilm as stated earlier.
On the train, Eve's room is identified as Car 3901, Room E. When the porter delivers a message from her, he identifies it as "from the lady in room 3901."
Someone who resembles Thornhill gets off the train without a suitcase; it's possible to confuse that person with Thornhill, who has a suitcase under his arm.
During the scene in the diner at Mount Rushmore, a young extra boy in the background anticipates the surprise gun shot, fired by Eve. The diners are supposed to be unaware this is going to happen but the young extra boy covers his ears way before she draws the gun. The young extra boy must have known there would be a loud bang from the blank-filled pistol from previous takes and therefore covered his ears on the "printed" take.
In the Chicago P.D. patrol car after Thornhill's arrest at the auction house, the cop on Thornhill's right forgets to lean as they simulate a turn. Cary Grant can be seen giving the errant actor a poke in the arm.
Every indication is given throughout the film that the action takes place in the summer - the trees in NYC are in full flower, ditto the foliage at the Long Island estate, the Indiana cornfield landscape is scorched, the way people are dressed, especially in the Chicago as well as South Dakota scenes, etc. - yet the newspaper which the Professor and his colleagues read recounting the murder of Lester Townsend carries a late November date.
The film was actually shot from mid - late August through September, 1958.
The film was actually shot from mid - late August through September, 1958.
When the professor stands by a window, the entire background showing the Capitol building shakes for a brief moment, making it obvious that it is not real.
The newspaper showing the photo of Thornhill at the UN, knife in hand, is dated Tuesday, November 25, 1958. The next day, on which the crop duster sequence occurs, would be Wednesday, November 26. The corn would not be so tall at the end of November, and the weather would not be as sweltering as it is portrayed. The following day in South Dakota would be Thursday, November 27. Average temperatures at Mt. Rushmore at that time of year would not permit short-sleeved dresses and other summer garb. Thursday the 27th would also be Thanksgiving Day, and families would likely be dining at home, on turkey, rather than in a tourist cafeteria. Finally, the branches of the shrubbery on the mountain (on which Eve Kendall's shawl gets stuck) would not be covered in foliage.
When the professor brings clothes to Thornhill, who is confined to the hospital room for a few days, Thornhill starts to get fully dressed immediately. The professor sees Thornhill starting to get dressed but does not question why he's doing so since he's confined to the hospital room, in bed. Thornhill does, in fact. escape, clothed, out of the window after the professor leaves the room.
The news reporter on the radio said they were looking for a man accompanied by a 'blonde woman in her late twenties'. Eva Marie Saint (Eve Kendall) was already 35 when she played the part.
Eve's line "I never make love on an empty stomach" is overdubbed with "I never discuss love on an empty stomach".
At the end, when Thornhill is pulling Eve up onto Mount Rushmore, he says to her "Come along, Mrs Thornhill," but his lip movements don't match what he's saying.
The airstrip at Vandamm's place clearly seems to be a gravel strip. Yet, as the plane touches down, a brief tire screech is heard, as from a plane setting down on a concrete or asphalt strip.
When Eve and Roger are kissing after the porter leaves the compartment there is no movement nor is there any noise from the train. You can even hear Eve leaning against the wall of the compartment as it creaks as Roger presses against her.
When Thornhill escapes from the Mt. Rushmore house and runs over to the black Ford, he is shown opening the car door and just starting to get in while on the soundtrack the sounds of the door being closed and the ignition being turned on are heard.
When Thornhill and his mother are changing elevators you can see a crew member bend over in the reflection on a pane of glass.
As the plane crashes into the truck, wires are visible on the right-hand side of the screen.
During the climactic Mt. Rushmore scene at the end of the film, the top of the mountain set, and equipment, are clearly visible for a number of seconds.
There are a couple of shots looking out over the tops of the monument's heads. In one of them, two presidents face the other two. The actual monument has three presidents facing one.
As the drunken Roger is placed in the car by the kidnappers, waves can clearly be seen crashing into a rocky coast line with a large drop to the sea. The scene takes place in Glen Cove, New York, as evidenced by the police car, but there is nowhere on Long Island that has a coastline like this.
In the LaSalle Street Station scene in Chicago, the announcer calls the departure for the "New York Special" as 10:00 A.M. Central Daylight Time; however, the newspaper the Professor reads earlier in the movie dates the action to November, when Chicago would have been under Central Standard Time.
The address for the auction house is 1212 N. Michigan Avenue, Chicago, IL. Michigan Avenue North numbers stop at below 1000 where it becomes Lake Shore Drive.
As Roger Thornhill returns to the Ambassador East in Chicago after the traumatic scene in the cornfield, you can see a palm tree near the hotel. There are no palm trees in Chicago or anywhere in the Midwest.
At the United Nations, diplomat Lester Townsend (Philip Ober) tells Thornhill that his house in Glen Cove has been closed up while the U.N. is in session and that his wife has been dead for years. During the earlier trip to the house by Thornhill with the detectives, a woman posing as Mrs. Townsend lets them in and answers all questions to their satisfaction. A little cursory checking by the detectives would have turned up the fact that the house was unoccupied at the time and that Mrs. Townsend had died years earlier, facts which would have given more credence to Thornhill's story.
When Vandamm and company first tried to kill Thornhill/Kaplan, they tried to make it look like a drunk driving accident. A plausible plan because they didn't want to draw attention to themselves. Then why in the world would the try to kill him with a biplane cropduster? Not only would it have a very low percentage for success, it would in no way appear to be accidental. That's a pretty clumsy attempt by "professionals." Why not just drive up to him and give him the ol' "one behind the ear?"
Once Vandamm reads the newspapers' account of Roger Thornhill being accused of murder, he would have realized, from the description of Thornhill's history of employment on Madison Avenue and longtime residence in New York City at an established address, that Thornhill couldn't possibly be George Kaplan, who'd supposedly been staying at the Plaza after traveling around the country for the previous few months, trips which would have been reported in the story had Thornhill made them. A little easy checking by Vandamm would have confirmed Thornhill's identity as a prominent advertising executive and made him aware of what bunglers his henchmen are.
Initially, when the plane attacks Thornhill it flies low in order to hit him. Following that it tries to machine gun him down. It then goes back to the flying low tactic. A plane can't fly low enough to run a person down as if it was a car. It would mean a certain disaster for the plane. Also, the logical option is to use the machine gun but it ceases firing and goes back to the flying low tactic. The aforementioned makes no sense.
When Leonard and Eve are in neighboring phone booths, the dialogue silent to the audience through the glass, it is presumed Leonard is giving Eve instructions on what to tell Thornhill to get him to the place where he would be murdered in the cropduster incident. But part of their ruse is that Eve is pretending to be getting this information from George Kaplan, whom at this part of the story the spies think is the same person as Thornhill. With that belief despite all his denials, it is beyond all logic to convince Thornhill these instructions are from himself. Even if they are playing along with what they perceive to be his own ruse of not being Kaplan, Eve's volunteering to try to reach Kaplan and then actually getting an answer, should in the spies' mindset be a dead giveaway that they were giving him false information.
At the Chicago station when Eva tells Thornhill to take a bus to meet Kaplan, in the long shot with the column behind them, the boom mic is clearly visible wobbling above.
When Cary Grant leaves the train in Chicago, the Redcap uniform he is wearing is a perfect fit (if anything with the sleeves a little long). Yet when you see the man he got the uniform from, he is a very short little man whose clothes would never fit Grant, who of course is very tall.
Prior to his departure, Van Damm informs Anna the housekeeper that arrangements have been made for her to cross the Canadian border, to which she responds, "God bless you." This would not be an appropriate response for a Communist.
Theodore Roosevelt is misquoted by the Professor. He should have said, "Speak softly (he uses soft) and carry a big stick."
During the auction, someone bids $2000 for an item and the auctioneer says, "I have 2000." A short time later, the auctioneer says, "I have 2250" and the item ends up being sold for that amount, even though nobody has bid more than $2000 for it.
At the beginning when Thornhill grabs the cab, the secretary enters first but she doesn't scoot over and remains behind the driver. He then climbs over her and sits behind the front passenger's seat. This is not normal behavior. However, later on, when Thornhill gets dropped off, it becomes evident why they did this. Thornhill exists directly onto the sidewalk, then there's a medium shot of him as the cab pulls away; thus, it was done for the camera setup.