Professor Poopsnagle's Steam Zeppelin(1987)

Professor Poopsnagle, the holder of an important scientific mystery, was kidnapped and his mysterious disappearance undermines the world of science. His young grandson, who helps him in research, provides assistance to professor Garcia, a longtime colleague and friend of the scientist. Helped by a group of children spending their holidays in a secret camp in the valley, Professor Garcia and the young boy build a flying bus. They set off in pursuit of the kidnappers and an attempt, at the same time to complete Poopsnagle's unfinished work.