"What is the flight time?"
Translation:비행 시간은 어떻게 돼요?
~어떻게 되다: 어떻게 = how; and 되다 = to be, to become. Saying 어떻게 돼요 means "how does it become" which is more or less the same as a long-winded way to say "what is". Saying 어떻게 돼요 instead of 뭐예요 can be more polite, kind of like how one may say "could you tell me" instead of simply "tell me."