Factual error: When the action moves to England after the failed award ceremony, the British Union Flag hanging from the wall is upside down. The broad white band should be at the top left (nearest the top of the flag pole).
Factual error: In the section during the movie reel, there is footage of the 1939 world's fair in New York. The Unisphere is shown. Unfortunately, the Unisphere was constructed in 1964 for the 1964-1965 world's fair. The Perisphere (and Trylon) were the centerpiece of the 1939 fair. The Perisphere was a sphere 200 feet in diameter. The Unisphere is still standing in flushing meadows park in New York city.
Revealing mistake: When we see the new recruits at boot camp, they are wearing M1 Helmets. But if you look closely, they have rivets through the sides of each helmet where the chinstrap bales would be. In reality, the M1 helmet chinstrap bales were and continued to be welded onto the shell of the helmet. This indicates the helmets in the film are probably plastic replicas with the bales being riveted in place.
Deliberate mistake: In the scene where they break into the train from its roof, you can notice that despite the high speed and the consistent wind, Captain America's fellows have no difficulties in running, standing up still, and even jumping, like they felt no air resistance. Moreover, you can see that their hair is not moving at all, completely missing to realize any "windy" effect.
Factual error: In the closing credits, during the montage of World War II posters, the American flag appears wrapped around a cannon barrel. The flag has 50 stars, not the then-correct 48.
Factual error: At one point the Colonel references "MI-6" which is the current British term for their intelligence service. However this terminology didn't exist until after the war. During WWII it would have been referred to as Special Operations Executive or SOE.
Factual error: The German Stielgranaten - as well as other traditional German WW II hand grenades - did not have a ring and pin like the ones the Allies used, but had a string which had to be pulled hard in order to arm them. Thus they wouldn't make such a distinct 'ping' as they do in the movie.
Continuity mistake: When Captain America is ready to jump out the plane, he is looking at Peggy Carter when he reaches for his goggles, the angle changes to the outside and Cap is seen with one hand out the plane and the other in, with his goggles up. it switches back inside and his goggles are on.
Continuity mistake: The windscreen on the flying wing appears to be completely intact when it is discovered in the present. Not only is it implausible to believe it survived a head-on crash without being damaged, but also during the final fight on board, it receives several bullet holes.
Factual error: The early scene in the movie theatre is in 1943. In the opening newsreel a Sherman Firefly tank is shown. This tank was not made until early 1944 [the long barrel and spherical muzzle brake are distinctive]. Even if we were to assume the tank was made earlier in the Marvel Cinematic Universe due to people like Stark working for the Allies it still would not be shown in a newsreel anyway for security reasons, with German spies and sympathizers present in the US during the war. (00:09:30)
Continuity mistake: During the final battle on board the 'flying wing' between Captain America and Red Skull, the finish on CA's shield appears damaged and scorched. Yet in the opening sequence of the movie when his shield is discovered under ice inside the frozen 'flying wing' it appears undamaged.
Character mistake: Dr. Erskine says he lives in Queens at 73rd Street and Utopia Parkway. Actually, 73rd Street is well to the west of Utopia Parkway (both run north-south). Erskine must have meant 73rd Avenue, which does cross Utopia Parkway.
Factual error: In the scene at the World Expo, the flags are being displayed. Next to the US flag is the Bahamian flag. The Bahamas didn't have a flag until 1973 when it gained its independence. It used the British Flag or the "Union Jack" since it was still a part of Britain. Also, the flag disappears a few seconds later.