Nếu bạn đi đúng giờ, bạn sẽ đến sân bay sớm.

Vietnamese often repeats the subject in both parts of a conditional sentence:

• Nếu bạn đi đúng giờ = if you leave/go on time
• bạn sẽ đến sân bay sớm = you will arrive at the airport early

So repeating bạn is completely normal. In English, we also usually repeat the subject: If you leave on time, you will arrive early.
You generally cannot just omit the second bạn in careful standard Vietnamese.

Nếu means if. It introduces the condition, just like if in English.

Structure:

• Nếu + clause, main clause

So here:

• Nếu bạn đi đúng giờ = if you go/leave on time

Very often, the result clause may be introduced by thì, especially in spoken or more explicit Vietnamese:

• Nếu bạn đi đúng giờ, thì bạn sẽ đến sân bay sớm.

This is also natural. In your sentence, thì is simply omitted.

Đi basically means to go, but in many contexts it can also be understood as to leave.

In this sentence, Nếu bạn đi đúng giờ is most naturally understood as:

• If you leave on time or
• If you go at the right time

English often prefers leave on time because the idea is about departing at the proper time so that you arrive early.

So đi is flexible here, and context tells you the most natural translation.

Đúng giờ means on time, punctual, or at the correct/scheduled time.

Breakdown:

• đúng = correct, exact, right
• giờ = hour, time

Together, đúng giờ means doing something at the proper time.

Examples:

• đến đúng giờ = arrive on time
• đi đúng giờ = leave/go on time
• làm việc đúng giờ = work on schedule / on time

Sẽ marks future time, similar to will in English.

So:

• bạn sẽ đến sân bay sớm = you will arrive at the airport early

However, Vietnamese does not always need an explicit future marker if the meaning is already clear from context. So you may also hear:

• Nếu bạn đi đúng giờ, bạn đến sân bay sớm.

This can still be understood, but sẽ makes the future result clearer and more natural in this kind of sentence.

Đến means to arrive at, to reach, or to come to.

So:

• đến sân bay = arrive at the airport

In Vietnamese, the verb comes before the place:

• đến trường = arrive at school
• đến nhà = arrive home / arrive at the house
• đến sân bay = arrive at the airport

This is different from English, where we usually need a preposition such as at.

Sớm means early. In Vietnamese, adverbs like this often come after the verb phrase.

So:

• đến sân bay sớm = arrive at the airport early

That word order is very normal in Vietnamese:

• verb + place + time-related adverb

More examples:

• đến lớp sớm = arrive at class early
• về nhà muộn = get home late
• dậy sớm = wake up early

The comma is common and helpful, because it separates the if-clause from the result clause:

• Nếu bạn đi đúng giờ, bạn sẽ đến sân bay sớm.

In informal writing, people may sometimes omit it, but using the comma is clear and standard.

Yes. You can say:

• Nếu bạn đi đúng giờ, thì bạn sẽ đến sân bay sớm.

This is very natural. Thì helps mark the result part: then / in that case.

So these are both correct:

• Nếu bạn đi đúng giờ, bạn sẽ đến sân bay sớm.
• Nếu bạn đi đúng giờ, thì bạn sẽ đến sân bay sớm.

The version without thì is a bit more streamlined.

Yes. Bạn can mean:

• you singular
• you plural, in some contexts
• sometimes friend

In this sentence, it clearly means you. Vietnamese pronouns depend heavily on relationship, age, and social context, so in real life another pronoun might be used instead, such as anh, chị, em, cô, etc.

For example:

• Nếu anh đi đúng giờ, anh sẽ đến sân bay sớm.
• Nếu em đi đúng giờ, em sẽ đến sân bay sớm.

So bạn is a neutral learner-friendly choice, but not the only possible pronoun.

Yes, that is a reasonable literal translation.

Word-for-word-ish:

• Nếu = if
• bạn = you
• đi = go / leave
• đúng giờ = on time
• bạn = you
• sẽ = will
• đến = arrive at
• sân bay = airport
• sớm = early

But in natural English, leave on time often sounds better than go on time in this context. So the Vietnamese wording is simple, but the best English translation may vary a little depending on style.

Yes, sometimes. Vietnamese often omits words when the meaning is obvious from context.

Possible variations:

• Nếu đi đúng giờ, bạn sẽ đến sân bay sớm.
  The first bạn is omitted because it is understood.
• Nếu bạn đi đúng giờ, sẽ đến sân bay sớm.
  Less balanced, but may occur in informal speech.
• Nếu bạn đi đúng giờ thì đến sân bay sớm.
  The future meaning is understood without sẽ.

That said, the full sentence you were given is clear, standard, and very good for learners:

• Nếu bạn đi đúng giờ, bạn sẽ đến sân bay sớm.