When aircraft with secret gadgets aboard start disappearing all around the globe, "Maj. Hammond" (Ralph Richardson) reckons that there is something suspicious going on. His investigations - frequently interfered with by his aspiring journalist sister "Kay" (Valerie Hobson) - eventually, despite scepticism from the latest aircraft's manufacturers, manage to enrol budding pilot "McVane" (Laurence Olivier) into his cunning plan to identify and bring the perpetrators to book... As a story, it's all a bit far-fetched, but what gives it quite an edge is the really quirky - almost improv. style of…