If you are aboard a ship or plane, you are on it or in it.
例句
She invited 750 people aboard the luxury yacht, the Savarona...她邀请了750人乘坐豪华游艇“萨瓦罗纳”号。They said goodbye to him as he got aboard the train at Union Station.当他在联合火车站登上火车之际,他们向他道别。
英汉词典释义
prep.
在(船、飞机、公共汽车、火车等)上;上(船、飞机、公共汽车、火车等)
They were all aboard the ship last night.昨天夜里他们都在船上。
adv.
在船(或飞机、车)上, 上船(或飞机、车)
The diesels roared, the conductors jumped aboard, and off the train went.内燃机发出轰鸣声, 列车员跳上车厢, 火车开走了。