The Adventures of Mark Twain (1985 film)

The Adventures of Mark Twain, released in the UK as Comet Quest, is a 1985 American stop motion animated fantasy film directed by Will Vinton. It received a wider theatrical release, still limited to seven major cities, in May 1985. It was released on DVD in January 2006.

After having a bout of oneupmanship, Tom Sawyer, Huck Finn, and Becky Thatcher sneak aboard an airship piloted by Mark Twain in an attempt to become famous aeronauts. Upon discovery, they find that Mark Twain intends to pilot the airship to meet Halleys Comet. Worried that this goal will end in their deaths, the trio learn to fly the ship while conspiring to sabotage the voyage.After discovering the truth behind Twains journey, the trio recognize their folly, and the group navigates storms and treacherous skies with the help of a mysterious dark figure who turns out to be Mark Twains dark side. The two Twains merge and fly off to meet the comet, leaving the airship in the hands of the youngsters. ........

Source: Wikipedia