Factual error: The German planes in the movie should be Messerschmitt Bf-109E. However they're actually Hispano Buchon, a post-war version of the Bf-109 model, built in Spain. The Bf-109 was powered by a Daimler-Benz inverted V, and exhaust ports were at the bottom of the nose, not at the top as seen here. That's because the Hispano Buchon used the same engine as the Spitfire.
Factual error: The door of the garage next to the house is of the aluminum up-and-over type, not available until the late 1960's.
Factual error: When Goring arrives at Calais by train, you notice there is a huge mountain in the background. There are no mountains anywhere near Calais.
Factual error: The He-111s shown in the movie were in fact produced in Spain after World War II and powered by RR Merlin engines instead of Jumo 211, which had smaller radiators moved backwards, up to the landing gear bays.
Factual error: The message at the end of the film acknowledging the contribution by pilots from outside the UK is wrong in a number of details. Most obviously they mention a pilot from Israel, a country which did not exist until 1948 (In fact he was from the British Palestinian Mandate). They also omit any mention of the nine pilots from Denmark, and two Jamaican pilots who took part in the battle, and there was one from Egypt and one from Austria involved, who was also forgotten.
Factual error: In an early scene, there are some Spitfires which catch fire. They burn fiercely like the fabric covered Hurricane not the metal skinned Spitfire. Quote from my mother who served in WW2 on a Naval Air Station and saw them both burn. "Those Spitfires are burning like Hurricanes".
Factual error: Early in the movie as the Germans are moving landing crafts up to the coast in preparation for the invasion of England. At least one of the trucks hauling landing crafts is a "B" Model Mack which was not introduced by Mack Trucks until 1953.
Factual error: In the sequence where German bombers are flying in daylight over the Thames approaching West Silvertown two high rise council flats called Dunlop and Cranbrook Point are visible. They did not exist until 1966.
Factual error: Most of The Spitfires in the film are not the correct type - Mark 1's and 2's should be used but you get a mixture of mark 9's and 14's. You can tell the mark 1's from the 3 exhaust stacks, the later models had 6. There is one genuine Battle of Britain veteran spitfire in the film, P7350, a Mk IIA the only BoB veteran spitfire still flying and operated by the Battle of Britain Memorial Flight.
Factual error: When first introduced to the Poles' training flight and they break stating "repeat please", the front 2 aircraft are Hurricanes but the 3 remaining aircraft are the stand in 109's. If you look closely you can see the rear wing struts to the fuselage.