tapseunggwoni eobseumyeon bihaenggireul tal su eobseoyo.

탑승권 means boarding pass. It is not quite the same as a general ticket.

• 표 or 티켓 can mean a ticket in a broad sense.
• 탑승권 is specifically the pass you need in order to board a plane.

So in this sentence, it means you cannot get on the airplane without your boarding pass.

The particle 이/가 marks the subject.

Here, 탑승권이 없으면 literally means if a boarding pass does not exist or more naturally if you do not have a boarding pass.

Korean often expresses possession with 있다 / 없다:

• 탑승권이 있어요 = There is a boarding pass / I have a boarding pass
• 탑승권이 없어요 = There is no boarding pass / I do not have a boarding pass

So 이 is used because 탑승권 is the thing whose existence or non-existence is being stated.

없으면 is made from:

• 없다 = to not exist, to not have
• -으면 = if / when

So:

• 없으면 = if there is not / if you do not have

In this sentence, 탑승권이 없으면 means if you do not have a boarding pass.

The conditional ending changes depending on the verb stem:

• after consonants: -으면
• after vowels: -면

Examples:

• 시간이 있으면 = if you have time
• 돈이 없으면 = if you do not have money

를/을 marks the direct object.

The verb here is 타다, which means to ride / to board. The thing being ridden or boarded takes 을/를.

So:

• 비행기를 타다 = to ride / board a plane
• 버스를 타다 = to ride a bus
• 택시를 타다 = to take a taxi

That is why 비행기 takes 를 here.

Yes, 타다 basically means to ride or to get on a vehicle. Korean uses it much more broadly than English.

You use 타다 with many forms of transportation:

• 버스를 타다 = ride the bus
• 기차를 타다 = ride the train
• 비행기를 타다 = board / take the plane

In natural English, we often say take a plane or board a plane, but Korean still uses 타다.

탈 수 없어요 is the pattern for cannot ride / cannot board.

It breaks down like this:

• 타다 = to ride / board
• verb stem: 타-
• -(으)ㄹ 수 있다 = can, be able to
• -(으)ㄹ 수 없다 = cannot, be unable to

So:

• 탈 수 있어요 = can ride / can board
• 탈 수 없어요 = cannot ride / cannot board

Because 타다 ends in a vowel, it becomes 탈 수.

They are similar, but not the same.

• 안 타요 = do not ride / do not board
• 탈 수 없어요 = cannot ride / cannot board

The first expresses choice or simple negation. The second expresses inability or impossibility.

So in this sentence, 탈 수 없어요 is better because the meaning is not you choose not to board, but you are not allowed or not able to board without a boarding pass.

Yes. Korean often leaves out the subject when it is understood from context.

탑승권이 없으면 비행기를 탈 수 없어요 naturally means:

• If you do not have a boarding pass, you cannot board the plane
• or more generally, Without a boarding pass, one cannot board a plane

Korean omits words like you, I, or people very often when they are obvious.

This is about speech level.

• 없어요 = polite, everyday style
• 없습니다 = more formal
• 없어 = casual, plain speech to friends or younger people

So this sentence is in a standard polite style that is very common in conversation and learner materials.

The same sentence in other levels:

• 탑승권이 없으면 비행기를 탈 수 없습니다. = more formal
• 탑승권이 없으면 비행기를 탈 수 없어. = casual

Yes. That is a very natural translation.

Possible English translations include:

• If you don't have a boarding pass, you can't board the plane.
• Without a boarding pass, you can't get on the plane.
• You cannot board the plane without a boarding pass.

They all match the Korean meaning well. Korean uses the if structure literally, but natural English may turn it into without.