At the skating rink, when the Falcon and Iris get off the rink to smoke a cigarette, the Falcon lights a cigarette in the shot from the rink. He then lights it again when viewed from the opposite direction.
At the start of the film when the airliner is shown crashing the model is of a conventional small twin-engined airliner. In the live action shots after the crash it has the unusual twin horizontal tail structures supported by several vertical surfaces of the Capelis XC-12, also used in Five Came Back (1939).
When the bad guys take off in their car just after picking up the money by the water fountain, a cameraman or crew member is reflected in the driver's window.