“When pigs fly” is used to describe an impossible thing, something that will never happen. It’s often used humorously or sarcastically, especially as a comment on extreme ambition or deluded self-assurance. A similar phrase is, “when hell freezes over.”
The original version of the succinct “pigs might fly” was “pigs fly with their tails forward,” which is first found in a list of proverbs in the 1616 edition of John Withals’s English-Latin dictionary, A Shorte Dictionarie for Yonge Begynners.
Pigs have stood the test of time as the favored image of an animal that is particularly unsuited to flight. They are simply too bulky and too “earthy” to flit through the sky. The Illustrated Times referred to them in August 1855: “…pigs might fly. An elephant, too, might dance on the tight-rope.”
In Finnish, the expression is “when cows fly.” In French, the most common expression is “when hens will have teeth.”
One famous incidence of the phrase appears in Lewis Carroll’s Alice’s Adventures in Wonderland. “I’ve a right to think,” said Alice sharply, for she was beginning to feel a little worried. “Just about as much right,” said the Duchess, “as pigs have to fly …”
In the 1968 movie The Lion in Winter, King Henry II tells his wife, Eleanor of Aquitaine, “When pigs have wings!” She replies, “There’ll be pork in the trees come morning!”
An origin story that matches the phrase comes from a book by John Winthrop, an English Puritan explorer who settled in Massachusetts in 1630 and recounted his story in The History of New England, 1630-1649, published in 1908: “In this year one James Everell, a sober, discreet man, and two others, saw a great light in the night at Muddy River. When it stood still, it flamed up, and was about three yards square; when it ran, it was contracted into the figure of a swine: it ran as swift as an arrow towards Charlton, and so up and down about two or three hours.”
One wonders what they were drinking. Or smoking.
The image has been popular in Cincinnati, Ohio, which was a big pork packing center in the 1800s, and earned the name “Porkopolis.” To celebrate the city’s bicentennial in 1988, Andrew Leicester designed a new waterfront for the city, which included four flying pigs atop smoke stacks, to represent the pigs who gave their lives in the town’s slaughterhouse. Cincinnati hosts the Flying Pig Marathon each year and, in 2000, the city center was decorated with pig sculptures in a project called the Big Pig Gig.
The most famous flying pig is the inflatable pig seen at Pink Floyd concerts. It all began in 1976, when artist Jeffrey Shaw built a prop for the album cover of the 1977 album, Animals. The pig made news when it broke free of its moorings during the photo shoot and was seen by airline pilots. If I were a pilot, would that make me stop drinking? Or start?
Since I’m a writer, my favorite story is about American author John Steinbeck, who was told by his professor that he would be an author when pigs flew. When Steinbeck eventually became a novelist, he started to print every book he wrote with the insignia Ad astra per alas porci (to the stars on the wings of a pig). He sometimes added an image of a flying pig, called “Pigasus.”