the fly-by-night operator不守信用的投机商
We're not fly-by-night operator我们不做一锤子买卖
a fly-by night operation管理水平很差
ADJ（形容词） A fly-by-night businessperson is someone who wants to make money very quickly, without caring about the quality or honesty of the service they offer. 唯利是图的 [非正式][ADJ n]
...fly-by-night operators who fail to complete jobs.
...不能完工的奸商们。