Ralph Waite (voice of Shadow) replaced Don Ameche, who died in 1993 after making the first film.
Four American Bulldogs share the role of Chance, four Golden Retrievers share Shadow, and six Himalayan cat performers carry the part of Sassy.
Laurence Fishburne was initially cast as Riley before Sinbad took over.
Throughout the film, Sassy is seen licking her paws, sometimes as a haughty commentary on the superiority of cats. For this, fish oil was placed on the paws of the cat and naturally licked off.
At the airport, the pets are loaded into kennel carriers so that they will travel with the family by plane to Canada for vacation. The pets converse and we realize that Chance is worried that they are being sent to "the bad place" and separated from their family forever. As the carriers are traveling out to the plane on a moving baggage cart, Chance starts to rock his cage to escape. His carrier is knocked off the cart which is then hit by an oncoming cart and it breaks open. Sassy is able to unlock her carrier and, once free, she unlocks Shadow's carrier as well. The three, determined to find the Seavers, set off through the airport, up and down luggage conveyors loaded with suitcases and boxes and finally out onto the airfield where they watch the plane that is bound for Canada take off over their heads. This very complicated sequence was shot in many cuts with both live and fake animals being used. The matching "stuffies" were used at some point during filming to depict all three animals. The dog portraying Chance was trained in pre-production to jump around inside the kennel, making it rock back and forth. The kennel itself was actually secured to the vehicle so that the dog could jostle it and have no chance of knocking it off onto the ground. When we see the carrier get knocked off the baggage cart and hit by the other vehicle, freeing Chance, it was a fake animal in the carrier. When Sassy opens the kennel carriers, the cat had been trained in pre-production to reach out of her own carrier and put her paws on Shadow's kennel door. The doors were actually electronically opened by remote control. In some of the sequence, we see the lead animals and other dogs in carriers. These carriers were tied down to the vehicles so that they had no chance of falling off. Trainers were dressed as airport personnel, so were able to be near-by the moving baggage cart. The area in the airport where the filming was done was cleared and only film personnel and animal handlers were permitted to be on hand. Once free of their kennels, the animals rush back into the terminal to try and find the Seavers. They run in through an opening in the terminal building and find themselves on the luggage conveyors before finding their way to the waiting area where they last saw their family. They realize that the Seavers must already be on a plane, so they turn around and go back out to the airfield, risking another climb on the conveyors. For the scenes where the animals were seen on the luggage conveyors, there was a good deal of pre-production training. Early in the training, the speed of the conveyor was very slow. Over a lengthy training period, as the animals became more accustomed to the movement, the speed of the conveyor was gradually increased. Later the luggage and boxes were added as obstacles. Each animal was prepped individually and eventually together.