Ich und meine Schwiegersöhne(1956)

Agathe Zausel doesn't have it easy. Not only could her doll factory be running better, but her sons-in-law Fred and Otto also seem to have nothing but fantasies on their minds instead of devoting their full attention to the family business. Fred has taken it into his head to secretly compose pop songs, while Otto is secretly designing a rocket plane. As they both try to keep their pastimes a secret from Agathe, she can only fear the worst.