This movie shows the real pilots who took part in bombing raids along the Kiel Canal in September 1939.
Looking back at this movie, Michael Powell described it as "an outrageous piece of propaganda, full of half-truths and half-lies, with some stagy episodes which were rather embarrassing and with actual facts which were highly distorted." In its defense, it must be admitted that, completed as it was in late 1939, film makers had no idea of the intensity and extent of the destruction that the UK would soon experience during the Blitz, and so an unrealistically optimistic point of view was understandable and inevitable.
As soon as war was declared, Alexander Korda pulled film crews off other projects and assigned three directors to shoot at different locations simultaneously. Michael Powell was given the task of filming and recreating RAF bombing raids, Brian Desmond Hurst directed the scenes with Merle Oberon and Ralph Richardson, and Adrian Brunel directed the "emergency" scenes. The whole picture took only one month to finish, with filming only taking 12 days.
Because it was started and completed so soon after the declaration of war, and was seen to show how useful movies could be in wartime, this movie is considered to have done a lot towards allowing the British film industry to remain active throughout World War II. Conversely, just as during World War I, many cinemas were destroyed and/or closed, and filming effectively cut back to a considerable degree for the duration.
After a two-day run in Lima, Peru, the film had to be pulled from screening after the German colony there caused disturbances that directly concerned Peruvian sovereignty (Brooklyn (NY) Eagle, 23 March 1940).