In which situation would the safety briefing need to include information about flotation aids?

The safety briefing must include information about flotation aids specifically during emergency situations over water. This is crucial because passengers need to be aware of the steps they should take, including how to properly use flotation devices, in the event of a water landing. A water landing presents unique hazards that require immediate action and awareness of available resources for survival.

In normal flight conditions, smooth landings, or while taxiing to the terminal, there is typically no immediate risk of needing flotation devices. Therefore, the emphasis on flotation aids is only necessary when there's a real possibility of encountering water in an emergency scenario, ensuring that passengers are prepared to respond quickly and effectively in such an event.