fly-by-night

Definition from Wiktionary, a free dictionary

[edit] English

[edit] Noun

fly-by-night (plural fly-by-nights)

1. A creatures which flies at night; a nocturnal flier or traveler.
2. One who departs or flees at night in order to avoid creditors, law enforcement etc. (often used attributively).

   Do not give your credit card number to that fly-by-night operation.

3. (idiomatic, derogatory) Businesses that appear and disappear rapidly, or that give an impression of transience.
4. (idiomatic, derogatory) Traveling businessmen and tradesmen.

[edit] Usage notes

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.