(一):Isn't it time to say goodbye?是不是到时间了？

Isn't it time to say goodbye?
是不是到时间了？
Oh yes. Time is up.
哦，是的。到时间了。
The time has come to say goodbye.

Well, I suppose we should say goodbye.

(二):Have a nice trip.祝您一路顺风。

Have a nice trip.
祝您一路顺风。
Many thanks.
多谢。
All good wishes for a safe and delighted flight!

Wish you a pleasant journey.