The principle is simple. Give the sailors and airmen something that floats. But finding a substance that doesn’t become waterlogged is crucial. Many substances float for a while, but lifejackets need to float for hours and even days.
Milkweed is a plant regarded as a nuisance by gardeners and farmers. entomologists prize it for its ability to attract butterflies, but it true value became apparent in the early 1940s, when demand for lifejackets rose sharply.
Historian Gerald Wykes recounts how Michigan provided large amounts of milkweed for the nation’s warriors:
Late in World War II, the common milkweed was often the only thing that kept a downed aviator or soaking-wet sailor from slipping beneath the waves. The plant’s floss was used as the all-important filler for flotation devices.
Among many lives saved at sea by such flotation devices were those of President George H.W. Bush, who survived his aircraft’s crash in an inflatable raft, and Louis “Louie” Zamperini, whose raft drifted over 2,000 miles during 43 days after his airplane crashed.