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...她邀請(qǐng)了750人乘坐豪華游艇“薩瓦羅納”號(hào)。They said goodbye to him as he got aboard the train at Union Station.當(dāng)他在聯(lián)合火車站登上火車之際，他們向他道別。
英漢詞典釋義
prep.
在（船、飛機(jī)、公共汽車、火車等）上；上（船、飛機(jī)、公共汽車、火車等）
They were all aboard the ship last night.昨天夜里他們都在船上。
adv.
在船(或飛機(jī)、車)上, 上船(或飛機(jī)、車)
The diesels roared, the conductors jumped aboard, and off the train went.內(nèi)燃機(jī)發(fā)出轟鳴聲, 列車員跳上車廂, 火車開走了。