The seats in many airplane
s have cushions that can be used to float in water. They have straps on the underside
, for the user to hold onto. The airline safety video
they make passengers watch typically states, "In the event of a water landing
, the cushion under your seat can be used as a flotation device
I believe a life preserver refers more specifically to those orange things you wear around your neck, while "flotation device" suggests a less user-friendly lifesaver.