Fly by night

The phrase fly by night is a derisive term for businesses that appear and disappear rapidly, or that give an impression of transience. It has also been applied to individual traveling businessmen and tradesmen. The phrase implies that the quality of work done or goods sold is shoddy enough that the person responsible must leave town under cover of darkness to evade angry customers, or sometimes legal authorities.

A classic portrayal of a traveling salesman as a fly-by-night operator is the Broadway musical and film, The Music Man.

For the album by the popular music group Rush, see Fly by Night.