1. Welcome board!
欢迎登机!
还能这样说：
Welcome to go board!
Welcome to take the flight!
应用解析：
above board 诚实地;光明正大地;
a groaning board 丰盛宴席;
across the board 全面的;
go on board 上船;上飞机;
go on the boards 当演员
2. Please keep your seat belt fastened.
请系好安全带。
还能这样说：
Put on your seat belt, please.
Fasten your seat belt, please.
应用解析：
fasten one's eyes on sb. 盯住某人;
fasten the dyes into the cloth 使布深染而不褪色;
fasten upon a pretext 抓住某种借口;
fasten a crime on sb. 加罪于某人
3. Your seat is in the middle of the cabin.
您的座位在客舱中部。
还能这样说：
You can sit in the center of the passenger compartment.
You can take a seat in the middle of the passenger compartment.
应用解析：
cabin作名词：小屋，a log cabin 圆木小屋，舱房;船舱;
cabin还可以作动词：蛰居于小屋;把……关进(狭小的地方)。
4. Do you have any medicine for airsickness?
你们有没有晕机药?
还能这样说：
Do you have pills for airsickness?
Could you give me some airsickness medicine?
应用解析：
give sb. a taste of one's own medicine 以其人之道，还治其人之身