अपनी भाषा में प्लॉट जोड़ेंInventor Al Simpkins develops a new airplane fuel, "Economo," which he claims gets a thousand miles to the pint.Inventor Al Simpkins develops a new airplane fuel, "Economo," which he claims gets a thousand miles to the pint.Inventor Al Simpkins develops a new airplane fuel, "Economo," which he claims gets a thousand miles to the pint.