Although made at the height of WW2, this film is far from mere propaganda. As well as showcasing the fine acting and direction of Leslie Howard, it tells the story of a genuine hero. While the events of the film are heavily fictionalised, the basic story about RJ Mitchell's dedication to the creation of the perfect flying machine, (and then the perfect fighter aircraft) even at the expense of his health, is entirely true.
There have been many attempts to debunk the mythos surrounding the "Battle Of Britain" in recent years, largely as a result of social change. This film puts it back in context, as the struggle of a small group of individuals which helped win the war everyone fought.
As the character Crisp (David Niven), loosely based on real-life test pilot Jeffrey Quill, says at the close of the close of the film "They can't take the Spitfires Mitch, they can't take them...". The fact we all still speak English in England is a tribute to that. This film is a fine tribute to a great engineer and a great aircraft.