I don't know what one calls the genre of movies about passengers trapped on an airplane with criminals and summoning the courage to break free, but there are lots of movies with this basic plot, and what we have here may be one of the earliest entries into the genre. In order for the idea to work, the plane has to be big enough for people to move about from the cabin to the flight deck, and by placing the action on a clipper plane (at the time a state of the art luxury sea-plane), PRC, a notoriously low-budget "B" company, had plenty of opportunities to set a number of interesting confrontations in motion.
After a solid set-up in the fictional Caribbean island town of Puerte Nueve, the plane finally takes off and it's all action from that moment on. Jack Mulhall is dashingly handsome when he strips down to his undershirt, and his fight scenes are convincingly brutal. Ralph Byrd, former silent lead, was in his 50s when he made this film, and thus plays a second lead, but he is great as a tough newspaper reporter with a touch of John Barrymore bravura and a hint of Adolph Menjou suaveness. The two lead women, Carol Hughs and Julie Duncan, are fun as a squabbling Broadway sister act on the skids. Extra bonuses include some great supporting cast members, including our old friend I. Stanford Jolley, the rat-faced villain of a zillion TV and theatrical westerns; burly Australian stunt/actor Frank Hagney as a two-fisted heavyweight bar bouncer; Thomas Edwards doing a comic Latino turn; silent screen star Kenneth Harlan as the airship's captain; and tiny bespectacled Harry Depp as a tiny bespectacled airplane passenger.
Also, just for the sake of weirdness, check out Richard Clarke, who plays Carter's henchman Ryan. He is no rough-and-tumble match for Mulhall or Hagney, but he does play a tough, and so it is very unexpected to notice that he has the strangest speech affliction -- every time he says more than a sentence or two, his voice begins to shake and tremble like he is frightened or has some sort of nerve-malady. It's just very odd.
All in all, this was a great little movie of its type. Sure, it could have been better -- a shorter set-up and more tension in the final scenes, a staccato musical score to heighten the drama, a cuter and more compliant lead actress -- but it is certainly worth a viewing.
