The Car in the Sky - S1.E49

Speed and his family are on the way to the Grand Prix (which is the key race for the World Racing Championship) and their plane is forced down on to an island by a storm. On the island they find out: that the both the plane's and Mach Five's radios have been smashed; every other passenger is in a hurry to get where they are going; there are no plants on the island, and that the island is a likely a forgotten top secret base used during a war. Since the island is uncharted Speed has no idea where to send the homing robot nor if the oxygen would last long enough to get help. Speed learns that one of the other passengers has brought advertizing balloons. Using hydrogen from the base Speed turns the Mach Five into a dirigible, then they draw lots to see which three people will go to get help. After the drawing, Trixie gives her lot to a girl whose mother is dieing, and the rich man buys a lot from one of the other winners. Spritle and Chim Chim stow away and force Speed to throw everything