Learn Hardcore Korean: bihaenggiga gonghange dochakhaesseoyo.

가 is the subject marker that highlights 비행기 (“airplane”) as the doer of the verb 도착했어요. If you used 은/는 (비행기는), it makes 비행기 the topic and can imply a contrast or general statement (“As for the airplane, it arrived…”).

What does 에 in 공항에 indicate? Could it be 에서 instead?

Here 에 marks the destination (“to/at the airport”). It answers “where did it arrive?” If you used 에서, it would mark the location where an action takes place (“at the airport” as the setting of an action), but 도착하다 already implies movement toward. Using 공항에서 도착했어요 would sound odd because 도착하다 itself means “to arrive at.”

What is the dictionary form of 도착했어요, and how is it conjugated?

The dictionary (infinitive) form is 도착하다. To make it polite past tense:

Drop -다 → 도착하-
Change 하 to 했 (since 하다 verbs form past with 했) → 도착했-
Add -어요 → 도착했어요 (“(it) arrived”).

What’s the difference between 도착했어요 and 왔어요 when talking about arriving?

도착했어요 (from 도착하다) specifically means “to arrive” at a place.
왔어요 (from 오다, “to come”) can also mean “arrived,” but is more general (“came”). When you want to emphasize the arrival event itself, 도착했어요 is clearer.

Could I say 도착했습니다 instead of 도착했어요?

Yes. 도착했습니다 is the formal polite form (-ㅂ니다 ending). Use 도착했어요 in everyday polite conversation, and 도착했습니다 in more formal situations or announcements.

Can I omit 비행기가 if the context is clear?

Absolutely. Korean often drops the subject when it’s understood. You can simply say 공항에 도착했어요 if everyone knows you’re talking about the airplane.

Is the word order fixed? Could I say 공항에 비행기가 도착했어요?

Yes. Korean is flexible with word order because particles mark roles. Fronting 공항에 or 비행기가 can add emphasis or set context, but the verb must remain at the end.

Why isn’t there an object marked by 을/를 in this sentence?

도착하다 is an intransitive verb (no direct object). It describes the subject’s arrival; there’s no object receiving action, so 을/를 isn’t used.

If I wanted to say “The airplane departed,” what verb and structure would I use?

You’d use 출발하다 (“to depart”). In polite past tense: 비행기가 공항에서 출발했어요 (“The airplane departed from the airport”). Here 에서 marks the starting point.