Revealing mistake: When Wade gets shot, watch the shot where Upham brings the bags up to the injured medic. The next shot there is some fog which then reveals the injured medic. In this shot, watch carefully as the cast rips away the medic's shirt. If you look near the neck, you can see the fake stomach vest he is wearing for a split second - when the actor realises he ripped too far up, he quickly covers it back up. (01:28:43)
Revealing mistake: In the opening sequence Cpt Miller is wading through the sea with another man. You can see an odd looking square-shaped object clearly through his wet uniform. It may come as no surprise that a second later he is shot dead centre of the pocket. The object was obviously a charge. (00:07:45)
Revealing mistake: Just before the two American soldiers slap their grease coated "sticky bombs" on the passing German Tiger tank, you can clearly see two identically shaped grease stains on the first two wheels. Presumably nobody remembered to wipe off the wheels of the tank after a rehearsal or previous take of the scene.
Continuity mistake: When Miller is collecting Upham from the group of translators and map readers, Upham is so confused and clumsy that he knocks everything off the table onto the floor (e.g. typewriter and helmets). Told by Miller to leave everything except his helmet, Upham picks up a German one by mistake. When sent back to the table to get his own, everything has miraculously jumped off the floor back onto the table. (00:40:30)
Revealing mistake: In the scene where the American soldiers are in the village listening to the French music on the record player, take a look at the stone pillars at either side of the doorway. The bullet patterns are all the same on each stone block. No doubt the same mould was used. (01:56:00)
Continuity mistake: When Jackson has been given the dog tags to search through he looks for a place to sit. In this scene you see a black box with two yellow boxes at either side in the background. In the next scene the yellow box on the left has magically jumped up onto the black box in order for Jackson to kick it off and sit on it. (01:17:45)
Revealing mistake: In the Omaha Beach fight when the soldiers are ordered to gather more weapons and ammo, there is a massive explosion shortly after - if you look closely you can see the wires used to pull the unfortunate victims into the air. (00:16:25)
Continuity mistake: In the scene when they defend the bridge in Ramelle there is a soldier who wants to attach a stick-bomb at a German tank. When he walks out to the tank you see that he is wearing a beige uniform. In the next shot you see that the uniform has changed into a dark green, and you also see that it is a puppet that explodes. (02:08:15)
Continuity mistake: When Miller first hits the sand at Omaha a mortar round blows up behind him. He kneels in the sand, his face covered with bloody water. Seconds later a young soldier shouts at him and suddenly Miller is chest deep in the water with a clean face. Also his helmet liner strap changes position across the visor of his helmet. (00:08:35 - 00:09:50)
Continuity mistake: In the opening scene, when old James Ryan's family is behind him in the wider shot, one of the three blonde girls at the back has her hair over her ear and her right hand down by her side. In the following closeup of her, her hair is now behind her ear and her hand is up by her bag strap. (00:01:30)
Continuity mistake: During the Omaha beach scene, when Miller, Horvath and a few other soldiers are at the front of one of the bunkers trying to get past the firing squad, he puts down his knife with the mirror attached and grabs his gun, holding it underneath, but in the following shot he is holding it at the top. (00:19:35)
Continuity mistake: At the end when Tom Hanks has just died, there is a distant shot of Ryan standing there in disbelief. By Tom Hanks left leg is a helmet, upside down. The next shot is from above and the helmet has flipped over.
Continuity mistake: At the end of the Radar Station Battle, Miller is yelling for Upham to bring their gear. As told he does. Watch carefully. Just as he picks up the gear, he has a green strap on his chest. when you see a shot of him running, the strap is gone. (01:25:10)
Continuity mistake: When Miller's men reach the town where the first Ryan is (the wrong one), Miller tells Ryan the bad news about his brothers. When Ryan starts to cry and leans over to his captain the captain's hand is on Ryan's head, but in the following shot it is on the top of his back. (00:59:25)
Continuity mistake: In the scene where Tom Hanks releases the German POW, he ties a black blindfold around the prisoner's eyes. Notice how narrow the blindfold looks. In the next shot Upham is guiding the prisoner and instructing him, and the blindfold all of a sudden becomes very broad. (01:34:00)
Continuity mistake: In the final battle in the French Village, the Americans are attacked by two Tiger tanks, two Panzer tanks, etc. The Americans use a sticky bomb to turn the first Tiger into a roadblock. If you look at the roadwheels of the tank when the troops are attaching the sticky bombs, you can see that one of them has a large chunk of rubber missing. Later on, when Capt. Miller is staring down the second Tiger as it crosses the bridge, you can see that it too has a large chunk of rubber missing from the same roadwheel - same tank.
Continuity mistake: During the beach scene, Miller is kneeling at the rear of a Belgian fence talking about the beach being pre-sighted. There is a soldier in front of the fence who gets shot three or four times. If you look the first scene, he gets shot in the upper leg area, then when Miller moves out from behind the obstacle, the bullet wound has magically disappeared. (00:11:15)
Continuity mistake: At the beginning of the film when we see Tom Hanks below the big bunker, and he tells Jackson to get in an impact crater, Jackson kisses his cross with his right hand, but in the following shot, he is suddenly holding his rifle. (00:20:20)
Continuity mistake: When Miller's men are about to take the bunker under the radar tower, they are kneeling on the ground behind some bushes discussing their flanking moves and Jackson is about two feet away from Reiben to his left, but when it cuts Jackson is now behind Reiben. (01:22:35)
Continuity mistake: During the Omaha Beach scene where Captain Miller is at the front of the concrete bunker and calls upon Jackson to get into one of the impact craters, Miller moves behind Jackson. When Miller makes the move for the diversion he puts his hand on Jackson's right shoulder but in the following shot Miller is at least 2 to 3 feet away from Jackson. (00:20:20)
Answer: These were barrage balloons, commonly used during the war. They are used to stop low level bombing and low level fly bys by enemy fighter planes. The cables attached to the balloons are designed to cut through the wings of the aircraft and to bring them down, so any pilot would have to fly above them, and the balloons would also restrict the view from above.