Factual error: In this scene we see two soldiers fire a heavy calibre machine gun into a armoured personnel carrier, which is only a few metres away. As they fire there is a two second delay, then we see the bullets hit the target vehicle. In reality there would not be a two second delay.
Factual error: It is true that Richthofen was killed during an aerial battle with a Canadian pilot; but it was not by the pilot (in the movie, his counterpart Brown) himself, but by one of the Australian machine gunners on the ground (it is still not for sure which one of the gunners did it, though).
Factual error: At Portobello Market, when the kids are eating, there's a sign that reads "cookies." No chance there would have been anything like that in 40's London. It would definitely have read "biscuits."