white tail
n.— «The bigger worry for both Airbus and Boeing are the dreaded “white tails,” jets that come off the assembly line with no waiting buyers because the airline that ordered them has canceled or gone out of business. White tails get their name from the fact that buyers’ corporate logos aren’t painted on until just before delivery.» —“Airbus, Boeing face specter of ‘white tail’ jets” in Paris, France Associated Press Dec. 4, 2008. (source: Double-Tongued Dictionary)
Further reading
Two examples of adynaton, the rhetorical term for playful exaggeration suggesting that something will never happen, involve animals’ tails. One German expression translates as “It’ll happen when the hounds start barking with their tail,” and a...
Mitchell from Arlington, Texas, wonders about his father’s expression: If a bullfrog had wings, he wouldn’t bump his butt. It’s been around since at least the early 1900s, and is a variation on an older expression, If pigs had wings, they could fly...