When Fred and Peggy walk to her car after lunch, she is no longer wearing a pearl necklace. Cutting to her close-up after the kiss, she is wearing them again.
When the three war veterans board the B-17, the insignia on the side of the fuselage is correct for post-World War II (after September 1945), a white star on a blue disc with white bars on the left and right sides of the disc. However, when the B-17 is taking off, there is a brief glimpse of just a white star on a blue disc with no white side bars, the official insignia used from August 1942 to June 1943.
When Peggy makes scrambled eggs and toast for Fred, she brings the eggs to the table, but not the toast. The next camera shot shows Fred taking toast from the table that was never brought there.
When Homer is talking to the obnoxious customer at the soda counter, Fred serves water at the customer's right hand, but in another shot, it's at his left hand side.
The three men have been in the plane taking them to Boone City for at least 24 hours but are all clean shaven when they arrive and are in the taxi.
Fred dropped bombs in Germany, while Al and Homer served in the Pacific Theater. When they got out, Fred would have been on the East coast and Al and Homer would have been on the West coast. Some have said that all three of them would not be in the same place to catch the same plane back home, but this is not necessarily correct. Having been part of a flight crew, Fred could have easily returned the B-17 he served in and flown it to any number of aircraft depots, which were on the West Coast, such as Davis-Mothan AFB in Tucson, Arizona. All three could have easily ended up in the same location, and the writers chose them to do so.
During Al Stephenson's speech at the bank get-together party, he talks about his division being in Okinawa. The 25th Infantry Division (Tropic Lightning), was part of the Luzon campaign that started January 1945 and ended with the divisions relief at the end of June 1945. At no time was the 25th in Okinawa. The divisions that did participate in the Okinawan campaign (April 1 - June 22, 1945) were the: 7th, 96th, 27th, and 77th Infantry Divisions of the army and the 1st, 2nd, and 6th Marine Divisions.
As Fred, Homer and Al are riding through Boone City in the cab, they briefly pass a shoe shine stand in front of a billboard advertising Rainier beer and ale. But Rainier was sold exclusively on the West Coast and would not be advertised or available in a Midwestern town like Boone City.
The sign on the facility for the military transportation unit mistakenly reads Air Transport Command. The correct name was Army Transportation Corps.After the war it was changed to United States Transportation Command (USTRANSCOM).
When Al introduces his wife and daughter to Fred and Homer at Butch's, he refers to Dana Andrews as Homer and Harold Russell as Fred. This was intended as a consequence of Al being drunk.
Near the end of the movie, when Fred climbs out of the B-17, the salvage man refers to Fred as flying for the Air Force. This is odd since the US Air Force wasn't established 'til the year after this movie was released. Fred would have flown with the Army Air Corp. Response: The term "Air Force" was used to describe the Army Air Corp years before the official creation of the Air Force in 1947.
When Fred Derry presses the tiled wall in the entrance of his wife's apartment building, it gives way slightly.
When Fred Derry climbs into the B-17's nose compartment at the salvage field, the nose section noticeably wobbles as he steps into it, indicating the nose is a separate, detached set piece. The nose section on a complete, intact B-17 would not move like that.
When Al is out with Milly and Peggy (but before they meet Fred and Homer again), a musician in one of the clubs is smiling broadly while playing, but he glances at the camera and changes his expression to a more serious one..
Harold Russell's obvious Bostonian accent seems somewhat out-of-place given the location in which the film took place.
Just after Marie tells Fred she's going to get a divorce, the shot changes to show Fred's face but you can see that Marie, whose face is now turned away from the camera, is still mouthing words inaudibly directed at Fred. They appear to be the last two words of her line, "What have you got to say to that?"
When Steve the bartender greets Homer at Butch's, Homer puts out his hand and says, "Go ahead, pal, it won't bite you." However, his lips say, "Go ahead, pal, it won't hurt you."
At the end of the film, Homer hands Fred the wedding ring and says, "Here's the ring. Don't lose it." However, his lips say, "Here's the ring. Don't drop it."
When Peggy and Marie are in the ladies room at the restaurant, the cameraman's left arm is visible in one of the mirrors.
(At around 86 minutes) Homer and Wilma are talking in the shed.
The shadow of a crewman's head is seen on the wall at the bottom
right side of the screen next to Wilma. It appears for 1 full minute.
When showing the baseball signs for the Beavers in Boone City, one can easily see the rugged Western mountains just behind the signs. Boone City is in the Corn Belt and it is as flat as a pancake in that region of the country.
Reflected on the car on the left side of the screen, when Fred kisses Peggy.
Although Boone City is in the Midwest, Homer Parrish, who supposedly lived his entire civilian life there, speaks with a noticeable Boston accent.
Near the beginning of the movie, Fred Derry says he met his wife Marie when he was in training in Texas. Later on, Fred tells Marie that he'll fix her a nice meal, like he used to do at the drugstore. Fred was no longer working at the drugstore when they met.
When Homer is target shooting inside his garage, Wilma puts her fingers in her ears and removes them before Homer fires a shot, then puts her fingers back in her ears after the shot is fired.