The Chinese translation of have a nice trip in Chinese is simply have a nice trip. This statement is usually said to the people who are travelling.
Have a nice trip! = Miłej podróży!
nice day
Have a nice trip = Bon voyage! (Not sure what you mean by "When you are flight".
¡Buen viaje! (Have a nice trip!)
bon voyage!
Buon viaggio.
"Nǐ zhǔ yì dài" is how you could phonetically say "Have a nice day" in Chinese.
Xinghui.
Perverted... -_-
旅行怎么样
好梦 "Hao Meng"
旅途愉快/Lǚtú yúkuài