The Vultures were originally going to be voiced by The Beatles. The band's manager, Brian Epstein, approached the Disney studios about having The Beatles appear in the film, and Disney had his animators create the Vultures specifically to be voiced by the band. But when Epstein took the idea to the Beatles, John Lennon vetoed the idea, and told Epstein to tell Disney he should hire Elvis Presley instead. The look of The Vultures, with their mop-top haircuts and Liverpool voices, are a homage to The Beatles; one bird's voice and features are clearly based on George Harrison's. That's What Friends Are For was originally to be done as a rock and roll song. When the Beatles departed the project, the song was rewritten as a barbershop quartet, to make it timeless.
This is the 19th animated feature in the Disney canon. It was the last to be personally supervised by Walt Disney and Disney's last animated feature of the 1960s. This was the first film the studio released after Disney's death in 1966, and it was dedicated to his memory.
Walt Disney died during production of this film. Many people wondered at what the studio's fate would be, particularly the animation division. The film performed extremely well at the box office, ensuring that the animators would not be put out of work. Had the film failed, it is likely that animation would have been closed down at the Disney studio.
When Gregory Peck was the President of the Academy of Motion Picture Arts and Sciences, he tried his hardest to get this film not only nominated for an Academy Award for Best Picture, but also to actually win the award. He resigned as president in 1970 when other members didn't agree with him about nominating animated films. The Academy finally reconsidered over 20 years later, allowing La Belle et la Bête (1991) to be nominated.