"When landing on water", they said, (and presumably not being dead) "Remove your jacket from its packet and place it over your head." The last three lines are, word for word, part of the script for Ryanair's safety demonstrations, which sound like part of a Limerick every time I hear them (>50 times in the last four years), even though the scansion is, admittedly, a bit stretched.
[penelope] Heard it again today on the way back to GC from England, and have to make a small correction: it's "Remove the jacket". Doesn't help the scansion though.