All fly-by-night antonyms

adj fly-by-night

• lasting — continuing or enduring a long time; permanent; durable: a lasting friendship.
• permanent — existing perpetually; everlasting, especially without significant change.
• dependable — If you say that someone or something is dependable, you approve of them because you feel that you can be sure that they will always act consistently or sensibly, or do what you need them to do.
• reliable — that may be relied on or trusted; dependable in achievement, accuracy, honesty, etc.: reliable information.
• reputable — held in good repute; honorable; respectable; estimable: a reputable organization.
• trustworthy — deserving of trust or confidence; dependable; reliable: The treasurer was not entirely trustworthy.
• long — having considerable linear extent in space: a long distance; a long handle.
• responsible — answerable or accountable, as for something within one's power, control, or management (often followed by to or for): He is responsible to the president for his decisions.