Paul vient en avion.

Because the subject is Paul, which is third person singular: he.

The verb venir (to come) changes depending on the subject:

• je viens = I come / I am coming
• tu viens = you come / you are coming
• il / elle / on vient = he / she / one comes
• nous venons = we come
• vous venez = you come
• ils / elles viennent = they come

So with Paul, you use vient.

Vient comes from the verb venir, which means to come.

This is an irregular verb, so its forms do not all follow the simplest pattern. In this sentence:

• venir = infinitive
• vient = present-tense form for il / elle / on

So Paul vient means Paul comes or Paul is coming, depending on context.

It can mean either one in English.

French present tense often covers both:

• Paul vient = Paul comes
• Paul vient = Paul is coming

Which English translation sounds best depends on context. If this is just a simple statement about how he arrives, English often prefers Paul is coming by plane or Paul comes by plane depending on the situation.

In French, a very common way to talk about means of transport is:

• en
  • vehicle

So you get:

• en voiture = by car
• en train = by train
• en avion = by plane
• en bateau = by boat

This is just the normal French pattern for many forms of transport.

Because en avion is a fixed transport expression meaning by plane, not in a plane in the literal sense.

French usually does not use an article in these expressions:

• en avion
• en train
• en voiture

So Paul vient en avion is not saying Paul comes in a plane word-for-word. It is using the standard French expression for by plane.

Yes, but it is not exactly the same in feel.

• en avion usually means by plane / traveling by plane
• par avion can also mean by plane, but it is often especially used for shipment, delivery, or sending something by air

For a person traveling, en avion is the most natural everyday choice here.

Because it follows the basic French sentence order:

• subject
  • verb
    • extra information

Here:

• Paul = subject
• vient = verb
• en avion = how he comes / means of transport

So the structure is very straightforward and similar to English:

• Paul comes by plane.

Vient is pronounced approximately like vyan, but with a nasal vowel at the end, which English does not really have.

A rough guide:

• vi- sounds like vy
• -ent here does not sound like ent in English
• the final sound is nasal: vjɛ̃

Important points:

• the final t is not pronounced
• the en sound is nasal

So the whole sentence is roughly:

Paul vyan ahn n-avion

That is only an approximation, but it helps as a starting point.

Normally, vient does not make a liaison with en, so you do not pronounce the final t.

However, between en and avion, speakers often connect the words smoothly because avion begins with a vowel. You may hear a kind of linking sound there in natural speech.

For a learner, the key thing is:

• do not pronounce the t in vient

Because Paul is a proper name.

In French, proper names usually appear without an article:

• Paul vient
• Marie arrive
• Jean parle

So just like in English, you simply say Paul, not the Paul.

It can mean either, depending on context.

French present tense is flexible. So:

• in the right context, Paul vient en avion could mean Paul is coming by plane
• in another context, it could describe a usual method: Paul comes by plane

If you want to make the meaning clearly habitual, French often adds something like:

• d’habitude = usually
• souvent = often

If you want to make it clearly about right now, context usually does that.

You would change the verb form of venir.

Examples:

• Je viens en avion. = I come / I am coming by plane
• Tu viens en avion. = You come / are coming by plane
• Il vient en avion. = He comes / is coming by plane
• Nous venons en avion. = We come / are coming by plane
• Ils viennent en avion. = They come / are coming by plane

So the en avion part stays the same, but the verb changes to match the subject.