In the original Rescuers film, the albatross Orville was voiced by Jim Jordan who died two years before this film released. The character was replaced with Orville's brother Wilbur, voiced by John Candy. This is a reference to the Wright brothers, Orville and Wilbur, the inventors and pilots of the first functional airplane.
This was the first 100% digital feature film ever made. The animation and backgrounds were done traditionally but all of the coloring, many effects and the final film printing was all done digitally. This was the first film produced with Disney's Academy Award-winning "CAPS" production system.
On its initial release, this film was preceded by the Mickey Mouse short subject The Prince and the Pauper (1990). Interestingly enough this was only the second Mickey Mouse short made since the 1950s, with the first being Mickey's Christmas Carol (1983) which was made to accompany the 1983 re-release of The Rescuers.
Second Disney animated film not to be a musical, though it is worth mentioning that McLeach and Wilbur both sing incidental songs while none of the characters in The Black Cauldron (1985) (the first) sing.
The first animated film to have the appearance of "multi-plane shots" with the use of computer layering and formatting as apposed to manually producing the shots with multi-plane cameras (previous Disney films had no multiple-plane shots or only two-plane shots).
The death of Jim Jordan in 1988 (who'd been Orville's voice actor in The Rescuers (1977)) was partially the reason why Orville's brother Wilbur appeared instead of him, seeing that the producers wanted to have all the voice actors from the first Rescuers film reprise their roles of their respective characters for the sequel, and not have any replacements.