Pirates use their flying submarine to kidnap children, sink and loot a cruise liner. They escape the navy by flying out of the ocean and dropping a bomb on the pursuing submarine but ultimately are defeated by their own careless behaviour. The film is a mix of live action, early special effects, and simple animation with one surprising twist: the cold-blooded pirate captain is a woman! By 1916, submarines were an established technology (the RMS Lusitania was sunk by a German U-boat in 1915) but a flying submarine was novel and the concept had staying power: Tom Swift Jr. built a 'Flying Seacoptor' in 1952, the "Flying Sub" was a favorite in 'Voyage to the Bottom of the Sea' (1964), and there have been numerous variations on the theme in Japanese tokusatsu films (e.g. 'Atragon' 1963). 'The Aerial Submarine' was the second 'futuristic weapon' film directed by Walter Booth (after 'The Airship Destroyer' (1909)) and although a bit of a creaky, silent relic, the film is sufficiently imaginative and entertaining to warrant watching.