With direct consultation from actual Battle of Britain veterans, pilots on both the English and German side, Hamilton set about recreating the events of the battle to the last detail, meticulously crafting costumes, mock-ups, using authentic settings, and leaving no major tactical or aesthetic detail of the battle out.
An all-star cast of players included Laurence Olivier as Hugh Dowding along with Robert Shaw, Michael Caine, and Christopher Plummer as British fighter pilots.
Hours and hours of aerial footage was shot for the many air battles, and the scenes filmed with the aircraft are so rare and impressive, that much of the footage created for the film is still recycled today in other films about the Battle of Britain. The most notable examples of this are in Piece of Cake and Dark Blue World, both of which sneak in shots from Battle of Britain in highly creative ways while at the same time, intermixing said footage with original material.
Technological limitations at the time make some of the optical effects dodgy, but the majority of the aerial footage is 100% real and extremely impressive. The only lacking effects are tracer fire, gun flashes, and debris - understandable given the limitations of the period - but the sheer number of actual planes makes up for this without question.
