Since "The Lion Has Wings" was made before the attacks on Britain had begun, the film had to rely on existing stock footage, including sequences lifted from the air raid featurette, "The Gap". Contemporary aircraft, many of which were obsolete by 1939, are a noticeable jarring element. The footage of a German bomber taking off is actually a German airliner (Focke-Wulf Fw 200); at least, it has the correct markings, but most of the biplane aircraft featured in the RAF air show were obsolete fighters. The addition of footage that was shot at operational bases, RAF Hornchurch, Hornchurch, Essex, and RAF Mildenhall, Suffolk, England, combined with studio work at Denham Studio, Denham, Buckinghamshire, UK, lent an air of authenticity to the production.