Not originally a Disney movie, the film was being made independently when midway through production the main production company, Producers Sales Organisation (PSO) collapsed. Walt Disney acquired the production in a liquidation sale, picking up all film rights for this film and several others, and also putting up the finance for its completion.
When MAX, the ship computer, is describing the animals he has on board, he said "That is a Feenastarus from the Pixar Elliptic". This was five years before Pixar, a fledgling special effects computer group at the time, teamed up with Disney, who produced this film.
The trivia item below may give away important plot points.
David's flight to Phaelon and back took "4.4 Solar Hours," while 8 years have passed on Earth, indicating that time was slowed down for David by a factor of about 16,000, which corresponds to a speed of about 99.9999998% the speed of light.