"There's no reason to become alarmed, and we hope you'll enjoy the rest of your flight. By the way, is there anyone on board who knows how to fly a plane?"
"The survival of everyone on board depends on just one thing: finding someone on board who can not only fly this plane, but who didn't have fish for dinner."
I recall a flight into Hong Kong where the cabin crew were scurrying up and down the aisles. Shortly after they began their galloping, there was voice on the intercom asking if there were any medical professionals aboard. The landing was a bit bouncy...