Olly, Olly, Oxen Free (1978)

Elderly, eccentric Miss Pudd (Hepburn) is the owner of a store she considers an antique shop but most would call a junkyard. She frequently refuses to part with her merchandise because of its sentimental value, but she does agree to sell some items to two small boys, Alby and Chris , who are repairing a hot air balloon that belonged to the older boy's grandfather, a stunt man named The Great Sandusky. They plan to take the balloon aloft to celebrate the man's birthday. (wikipedia)