I'd like to say goodbye to everyone.

我要向大家告别了。

What time are you going?

你什么时候走?

My plane leaves at 6: 45. Don't forget to drop me a line.

6 点45 分的飞机。不要忘记给我写信。

Well, goodbye and have a nice trip.

好，再见，祝你旅途愉快。'

drop a line 写信

trip .旅行，旅游 v.(把…)绊倒