当你准备出国留学并乘坐飞机时，以下是一些相关的英语表达和句子，你可以参考使用：
询问座位偏好
询问是否有座位偏好：
"Do you have a seating preference？"
回答想要靠窗座位：
"I'd like a window seat, please."
回答想要靠过道的座位：
"I'll take an aisle seat, possible."
行李相关
询问行李托运：
"Check one bag, please."
询问随身行李：
"only have one personal item."
安检和登机
询问如何前往安检处：
"How do I get to the security checkpoint？"
登机和飞行
询问座位号码：
"Where is my seat？"
询问手提行李放置位置：
"Where should I put this？"
询问是否可以换座位：
"Could you change my seat, please？"
到达目的地
询问登机口：
"Tell me the gate number, please."
其他心情短句
"Flying to study abroad is both exciting and nerve-wracking."
"Looking out the window at the night sky is breathtaking."
"I can't wait to start my new journey in a new country."
希望这些表达能帮助你顺利地进行留学之旅。祝你旅途愉快!