Continuity mistake: At the start of the film a Mosquito lands on runway 04 (NE). The next shot shows the aircraft still rolling down the runway, and the camera tracks past a weather vane showing the aircraft traveling in a south westerly direction.
Factual error: The dialogue refers to "Earthquake bombs" The real earthquake bomb, Barnes Wallace's Grand Slam weighed 10 tons and was designed to penetrate deep into the ground, shaking structures above. Even that would be unlikely to have an effect in the posed scenario.
Revealing mistake: In one shot, approximately just at the beginning of the actual attack, it shows a Mossie banking hard left at about 80° - the view is from the front. From the left wingtip, a "line" is shown continuing the dihedral angle to the edge of the frame. This is obviously a pair of control lines - so indicates it is a model being flown.
Answer: He says "You can't kill a squadron".
Bishop73