Factual error: Major Stewart addresses the Indian NCO as "Sergeant Major" and he is so described in the credits. There was no such rank in the British Indian Army. Indian cavalry sergeants were known as Daffadars. More senior Indian cavalry officers held VCO ranks (Jemadar, Risaldar and Risaldar Major) which had no British equivalent. Given the importance of rank and protocol, it is highly unlikely that a British commissioned officer would be unaware of this.
Factual error: At the end of the 'Goodbye' the men all board a train which leaves along a track on a seaside pier. The shot changes from this stylised vision to a shot of an Edwardian Lady alone on a railway platform. In the background is a 1970s, ie. modern, diesel train.
Continuity mistake: Nellie is called into Captain Brackett's office one day. Later, one of the girls asks her "What did the old man want this morning?" However, the scene at night between Billis and Cable shows that a whole day and night must have passed in between these two scenes. Therefore the nurse should have asked "What did the old man want yesterday?"
Other mistake: In the opening scene on the airplane, one of the men tells Lt. Cable, "The captain wants to know if you'd like to sit up in the cockpit with him?" Buzz Adams, the "captain" referenced in this line, is only a lieutenant. Admittedly, "captain" is a standard aviation term for the pilot of an aircraft, but it would be unlikely to be used in this situation, since the term has a specific military meaning.
Other mistake: The kids dare each other in a decrepit water tower which is mysterious in a number of ways: 1) Draining the water causes a powerful vortex, but the water level is not going down. 2) No one seems to work the bottom valve, but the vortex comes and goes. 3) It is absolutely impossible that anyone could swim through such a vortex, but Stu does. 4) The rotten roof breaks under the weight of little Billy (the ice-cream excess?) but carries his brother who weighs about 4 times as much. (01:27:00)
Continuity mistake: Charlie, disguised as a tree, enters a pipe to escape a German. When the German tries to pull Charlie out he separates the lower part of the tree costume along with Charlie's shoes. When Charlie emerges from the other end of the pipe he is still wearing shoes.
Continuity mistake: When the Austrian Emperor and Gustav's father die on the same day Gustav puts their photographs on a sideboard. The close-up of Gustav's father's picture shows a white background, in contrast to all wide shots. (00:44:15)
Factual error: During the first scenes of the film the Greek flag used is the current one, and not the one used at that time. The flag that should have been used is a white cross on blue.
Continuity mistake: Throughout the movie, Ho is referred to as "Captain Ho", however in the closing credits, his name is "Colonel Ho".
Continuity mistake: When John Mills is looking through the periscope whilst searching for the German battleship the side view shows him moving the periscope from right to left, but when it suddenly cuts to a shot of what he is actually seeing through it the periscope is strangely moving from left to right.
Factual error: None of the German tanks are accurate representations of German WWII types. They are all post war US variants. ie. M47 Patton Tanks. [Still a mistake, but an elaboration: This is a common problem in depicting German tanks: few, if any, survived the war. The few museum examples wouldn't be released for movie work, and certainly WHERE, some 20 years after the war, would one find a brigade's worth of running Tiger II tanks? Never mind that Kampgruppe Pieper, which Hessler's command is loosely based on, actually used Mark IV and Panther tanks. There was one King Tiger battalion, and it was in reserve well behind KG Peiper. The M47s versus the M24 Chafees (mistakenly called "Shermans" at times) is a fairly accurate comparison of the respective sizes, firepower, and other combat capabilities of the respective tanks. Some other movies, like "Kelly's Heroes", have their "Tigers" mocked-up with sheet metal, wire mesh, and sacking over a different type of tank (in that case, T-34/85s of the Yugoslav army are mocked up as Tiger Is, a fairly decent job).]
Continuity mistake: When Hugh O'Brian and Barbara Bouchet are driving up from the beach during the Japanese attack, they are in a Lincoln convertible. When the car explodes and goes over the cliff, it is either a Ford or Mercury convertible.
Continuity mistake: There's one peaceful scene where the point of view is from a boat drifting down a canal in town. As the boat drifts, it passes by some sort of monument, and a very clear full-body shadow of the camera man and camera is visible against the monument.
Revealing mistake: Towards the beginning of the movie, young Alexander tames a horse and then jumps on the horse and rides off. He is supposed to be riding bareback, but in one of the shots from a distance, you can tell that the actor's feet are in stirrups.
Continuity mistake: In the last scene, 2nd Lt. Blair is holding an army carbine on which the barrel is noticeably bent downward.
Factual error: In the shot where the three officers ride the aircraft elevator from the hangar deck to the flight deck after arriving aboard the admiral's carrier, you can briefly see some of the aircraft parked on the hangar deck, and they are jet aircraft. The aircraft have pointed noses, no propellers, and the fuselage shape and markings are consistent with first generation Navy carrier jets. These types were not in service until the mid-50s (See "Bridges of Toko-Ri").
Factual error: On a number of occasions uniformed Wermacht officers and men are shown saluting Albert Speer. Speer was a civilian and (obviously) not in uniform. Military men do not salute civilians.
Continuity mistake: When Lou is finally convinced that he won't get hurt being the umpire in the "Hit The Umpire" game, he runs to take his place then stops in front of the batter. As Lou runs to take his place he isn't wearing a baseball cap, nor is he holding one in his hands, but in the next shot, when he gets hit in the head by the batter, one has mysteriously appeared on his head.
Continuity mistake: At the end of the movie, Jack parks the car in front of a palm tree and walks onto the beach. The shot changes while he stands there for a few minutes. As the shot changes back to show him walking off the beach, the car is no longer in front of the tree, nor does he drive by during the credits. I hope he enjoys his walk back to Miami.
Continuity mistake: Just after Knoll has been beaten up we see Elwood sitting next to him. As Elwood switches on the light, we see that the left side of Knoll's face is covered in blood. After Elwood applies the bandage, the blood on his face has changed with much less blood on the left side. The blood was never wiped off.
Suggested correction: Speer, in his capacity as Reichsminister of Armaments and Munitions, would have been very recognizable to all Germans at this time and respected. Additionally, no Wehrmacht members actually salute or interact with Speer (by my memory), only Waffen-SS, who would doubtless be more loyal to a senior party member and willing to salute him. More so, if the entry refers to the Hitlergruß, the Hitlergruß was given regardless of rank per National Socialist ideology related to social equality.
One of Speer's many defences at his postwar trial was that he was a civilian, mistrusted by the military and never accorded military courtesies, which included them saluting him.