Some Mothers do 'Ave 'Em (1973)

Learning to Drive - S2-E8

Revealing mistake: When Frank is the pixie in Santa's grotto, a young boy fires something at Frank from his catapult. Although Frank reacts as being hit, the boy doesn't actually fire anything at all.

Learning to Fly - S3-E7

Frank: I didn't know what a girl was until I was twelve years old.
Betty: You must of done.
Frank: How could I. I'd never seen one.

eric 64

Trivia: Michael Crawford was the producers' third choice for the role of Frank Spencer. The part had been previously turned down by both Norman Wisdom and Ronnie Barker.