Mail Dog

The weather forces a mail plane to turn back. It drops the mail at Outpost #5, staffed by Pluto, who is to carry it to the next airport. His mission is briefly thwarted by a totem pole (hence, this is probably Alaska), but his real enemy is a rabbit who covets the blanket on Pluto's sled. They chase each other down some treacherous winding slopes before they end up at the landing strip, where the two of them crash into a snow bank and send the mail pouch right into the pilot's hand.