When Baker gets into his Spitfire it carries the squadron code 'LO', but the shots of the Spitfires taking off show them with the code 'SH' (used by 64 Squadron) and shots in the air show the code has returned to 'LO'.
Both night raids, Berlin and Dortmund, use footage of the same city by night.
The following items are 'goofs', but may have been made deliberately by the filmmakers in the interests of war-time security: The real 61 Squadron flew Hampden bombers, not Lockheed Hudsons. Hudson bombers were not used in bombing missions over Berlin, with the main role for these bombers being in Coastal Command in Europe. The real 32 Squadron, which Baker flies with in the Dunkirk scenes, flew Hawker Hurricanes and not Spitfires. When Baker gets in the Spitfire, it carries the squadron code 'LO' which was the code of the 602 Squadron and not the 32 Squadron he is supposed to be flying with (it used KT and GZ). 602 Squadron aircraft were used for shooting the film at Prestwick
Close shots of Baker in the Spitfire show a canopy more like a Hawker Hurricane canopy rather than a Spitfire. It is distinctly different to the canopies of the Spitfires in the background.
In many cockpit close-ups during air-combat scenes, the main part of the canopy is clearly absent in order to prevent reflections obscuring the viewers' view of the pilots. When it is present, on the Spitfires it's the wrong shape: a flat profile to the top edge rather than the actual bubble shape.
When the Lockheed Hudson crashes on the beach, it comes in impossibly slowly and comes to a stop impossibly quickly.
When Morley and Carol spend the day in 'Kent', the countryside looks far more like California and definitely isn't anywhere in Kent - e.g. the rugged hills in the background.
At the airfield, Carol's car is backed into by another car, hitting her's on the passenger side. But, in subsequent shots, there isn't even a scratch on her car.
Morely refers to a pilot baling out and being picked up 'in a launch' (i.e. at sea) 'south of Dunkirk'. South of Dunkirk is land.