Goofs

Fin's handkerchief in his breast pocket has a mind of its own.

There's lettering on the bottom of the rocker in the bedroom, probably prop identification, which disappears when the rocker overturns after the balloon blows up.

When Hardy falls out the window, the traffic on the street below is obviously not moving, and a still photo was obviously used as background; later on, the traffic is moving.

In the scene with Dr. Finlayson's "lung-tester", just before the giant balloon is about to burst, the Klieg lights are visible, reflected in the stretched latex of the balloon.

Mrs. O'Riley shows Hardy her refrigerator/radio, which plays a brassy tune. Hardy, who is suffering from "Hornophobia", doesn't react to the music, however, as he does throughout the rest of the picture whenever he hears horns.