German general Max Pemsel says: "Wir haben starke RADAR-störungen" (We have strong radar interference). The word "radar" was not used, perhaps even not known in Germany in 1944. They used a somewhat similar system, but called it "Funkmeßgeräte" (radio measuring equipment).
General Gavin is wearing a Senior Parachutist badge in 1944.The Parachutist Badge was formally approved on 10 March 1941. The senior and master parachutists badges were authorized by Headquarters, Department of the Army in 1949 and were announced by Change 4, Army Regulation 600-70, dated 24 January 1950.
When FO David Campbell is sitting, drinking a beer, we see someone standing and playing the piano in the background. The music heard is a slow rendition of the main theme of the movie, but the player is playing several notes with his right hand in the time only one note is heard in the soundtrack.
When the coded radio messages are read out in French, the awaited second line of the poem by Verlaine, "Blesse mon coeur d'une langueur monotone" ("Wounds my heart with a monotonous languor") sets the French resistance-group in motion. They leave the hiding Allied pilots and take up rifles. The next line heard on the radio before it is shut off is "J'aime les chats siamois" ("I like Siamese cats") But when the Germans hear and are recording the identical broadcast and hear the line of poetry, the coded message after that is a message heard before the French resistance-fighters heard the poetry line: "Daphné à Monique: Il y a le feu à l'agence de voyage. Inutile de s'y rendre." ("Daphne to Monique: There is a fire at the travel agency. It is no use to get there").
In the scene where Brig. Gen. Teddy Roosevelt, Jr. (Henry Fonda) lands at Utah Beach he can be clearly seen completely falling in the water as he steps of the landing craft (look for Fonda holding the walking stick), and with clothes completely soaked running up the beach. As the scene continues he crouches behind a beach obstacle with other officers. As the scene cuts to a closeup, his clothing is suddenly dry.
Early on, three German officers are talking with the coastline as a backdrop. One of the officers moves from right to left on the screen and when he is half way across he disappears (though he is still talking and can be heard). The ocean in the background repeats itself in the first second.
At the beginning of the movie when the German sergeant is taking coffee to the beach gunners we see his horse walking on the supposedly muddy ground, yet the shoes of the horses are not muddy and remain shiny throughout the length of the shot.
When General Cota meets up with General Thompson on the beach, he holds his cigar in his hand. After Cota says, "Think?" there is a quick cut to another angle, and the cigar is back in his mouth. Also, during this cut he uses both hands to take off his helmet, so where did the cigar go during this process?
When the French Commando Commanding Officer, Keiffer goes to get a tank he jumps out a window and is followed by another commando. This man is armed with a STEN Mk V (version with a wooden butt-stock and grips) when he jumps out the window, but when he runs across the street and takes cover with Keiffer before going to the bridge, he is armed with a STEN Mk II (version with steel skeleton butt-stock).
The "Rupert" paratrooper dummies dropped on D-Day were not the highly elaborate and lifelike rubber dummies shown in the film. The actual dummies were fabricated from sackcloth or burlap stuffed with straw or sand and were only crude representations of a human figure. They only appeared human from a distance during the descent and were equipped with an explosive charge that burned away the cloth after landing to prevent the immediate discovery of their true nature. A total of 500 dummies, accompanied by a handful SAS troopers, were dropped at four locations. The SAS played recordings of battle noise, set off smoke grenades and used their weapons to further enhance the deception. The whole operation was code named Operation Titanic.
When Lord Lovat leads his men to Pegasus Bridge, he can clearly be seen holding a Mannlicher Schoenauer Model 1903 carbine. One of the well-known eccentricities of Lord Lovat was that he always carried an old Winchester rifle in combat.
Colin Maud and his English bulldog, "Winston" are shown spurring "British" Soldiers into advancing up the beach. In actual fact the incident took place on the sole "Canadian" Beach, Juno - and Maud's dog was an "Alsatian" - the (then) politically correct designation for "German Shepherd".
The American paratroopers are incorrectly shown jumping with a jumpmaster standing in the plane and commanding them to "Go!" "Go!" one at a time. On D-Day, as on all combat jumps, the jumpmaster was always first out the door, with the rest of the paratroopers following immediately behind him, exiting the plane as fast as they could in order to land as close together as possible.
During the meeting with LtC Vandervoort, Brig. Gen. James M. Gavin is wearing branch insignia for Infantry. General officers at that time, (and until recently), did not wear branch insignia as they could command any type of unit.
Actors Robert Ryan and John Wayne - both in their mid 50s when the movie was made - were (and looked) some 20 and 30 years too old respectively to be portraying their real-life counterparts. Ryan's character Brig. General James Gavin was only in his mid 30s at the time of D-Day, and Wayne's character Lt. Col. Ben Vandervoort was only 27.
David Campbell (Richard Burton) is referred to in the explanatory text as "Flight Officer". He is actually wearing the shoulder rank insignia of Flying Officer, a low ranking officer in the RAF, equivalent to Lieutenant in the British Army. The rank of Flight Officer existed only in the Women's Auxiliary Air Force (WAAF) and was equivalent to the RAF rank of Flight Lieutenant. However, Campbell is correctly referred to as "Flying Officer" in the credits.
At the beginning of the film and again when the bombardment takes place prior to the invasion, The French farmer is seen watching Sergeant on horseback, delivering coffee to the beach gunners. First of all it's hard to believe the Germans would have allowed the French farmer to continue living in such close proximity to the ocean, where it would be possible to signal passing ships. And secondly, the shells detonating at such close proximity would have severely damaged if not demolished the house and the concussion would have killed the man and his wife.
When the second line of the Verlaine poem is said ("Blessent mon coeur d'une langueur monotone"), the subtitle reads "Wounds [singular] my heart with a monotonous languor". It should say "Wound", plural, as the subject of the verse is the plural "sobs".
The real Ouistreham casino had been destroyed and replaced by a German bunker before the D-Day landings, rather than having a bunker built into its basement as shown. The casino seen in the film was a disused building, set for demolition on the harbour at Port-en Bessin, Normandy.
Although Vandervoort and Steele are shown wearing "jump" boots, as befitted their status as paratroopers, Pvt. Schultz, also a paratrooper, wears two-buckle infantry "combat" boots. This type of boot was not worn to any degree on D-Day, even by the regular infantry (they wore ankle-high "field" boots with canvas leggings), much less the paratroopers.
During the sequence where the dummies were being dropped and the Germans were firing upon the aircraft, the Germans were firing an American quad-mount M2HB .50 calibre anti-aircraft gun (an M45 'Maxon Mount'), when the Germans were not equipped with this weapon, and would not have had a decent ammo supply even if they'd captured one (the 'tombstone' drums only carry 200 rounds each)
Before Oberstleutnant Priller and Unteroffizer Wodarczyk attack the Allies there is some stock footage of weaponless BF-108 "Taifun" liason/observation aircraft. Priller and Wodarczyk flew FW-190s on that mission.
The British pathfinders land on the HQ of General Von Salmuth, commander of the 15th army. However, the pathfinders had actually landed on General Reichert's HQ (Reicher was commander of the 711 division in Normandy) and also, Von Salmuth and the 15th army were actually at the Pas De Calais.
When LTC Vandervoort uses his flashlight to illuminate his map (while having his broken ankle taped), the flashlight illuminates the map, but displays a flashlight-shaped shadow in the center of the map (indicating the stage light used to "really" illuminate the map).
When the two men are on the rocking boat in the beginning, the straps on their helmets remain at a 90 degree angle to the car they're sitting in despite the boat's drastic rocking back on forth, showing that it was the camera, not the boat wobbling.
After the invasion begins, exterior closeup shots of an airplane dropping a canister shows it covered with water droplets. However, the water droplets are stationary. Had it been an actual aircraft in flight, the wind would be pushing the water backwards.
The image is flopped for one of the ships shown at the start of the naval bombardment (third close-up). The letters "HONNEU" on a plaque are reversed. The visible letters "honneu" are part of the French naval motto: Honneur, patrie, valeur, discipline (honor, country, valor, discipline).
When Major Werner Pluskat of the German army is in his bunker looking out to sea to try to spot the invasion forces, he is looking through an observation slit with his binoculars. The binoculars are clearly marked front and center as he is looking, "Made in Germany." In English.