Chuyến bay nối chuyến đến chậm.

Chuyến bay is the normal Vietnamese word for flight.

• bay relates to flying
• chuyến is a classifier/counter often used for trips, journeys, or scheduled runs

So chuyến bay is not literally two separate English-style words you need to translate one by one every time; together they function as the standard noun flight.

Because Vietnamese usually puts modifiers after the noun.

So:

• chuyến bay nối chuyến = literally flight connecting
• natural English = connecting flight

This is one of the most important word-order differences from English. English usually does adjective + noun, while Vietnamese often does noun + modifier.

Here, nối chuyến describes a flight that involves a connection or transfer to another flight. So it means connecting in connecting flight.

Literally, nối chuyến is related to the idea of connecting flights or making a flight connection.

In other contexts, it can also act more verbally, for example:

• Tôi phải nối chuyến ở Seoul = I have to transfer/change planes in Seoul

But in your sentence, it is modifying chuyến bay.

In this sentence, it functions like an adjective/modifier because it describes chuyến bay.

But Vietnamese words are often more flexible than English word classes. A form that looks verbal in one sentence can behave like a modifier in another.

So here, the best way to understand it is:

• chuyến bay nối chuyến = a connecting flight

Here it means arrive late.

• đến = arrive / come
• chậm = slow / late

In travel, schedules, and timing contexts, chậm often means late rather than slow. So đến chậm is naturally understood as arrive late.

A native English speaker might first read it too literally as come slowly, but that is not the intended meaning here.

Vietnamese usually does not need a word like was/is in a sentence like this.

The predicate đến chậm already means arrive late / be late in arriving. Vietnamese often allows this kind of direct structure without an extra linking verb.

So the sentence is structurally very compact:

• Chuyến bay nối chuyến = the connecting flight
• đến chậm = arrived late / is arriving late / came late

You know from context, not from the verb form itself.

Vietnamese verbs do not change form for tense the way English verbs do. So by itself, this sentence is tense-neutral. Depending on context, it could be understood as:

• The connecting flight arrived late
• The connecting flight is arriving late
• sometimes even The connecting flight comes late

In real life, the situation usually makes the time clear. If needed, Vietnamese can add time markers such as:

• đã for past
• đang for ongoing action
• sẽ for future

Vietnamese normally does not use articles like a, an, and the the way English does.

So chuyến bay nối chuyến can mean:

• the connecting flight
• a connecting flight

The context tells you which one is intended. In many real situations, especially when people are already talking about a particular itinerary, English naturally uses the, even though Vietnamese does not need a separate word for it.

Yes, but the meaning shifts a little.

• đến chậm focuses on the fact that the flight arrived late
• bị chậm focuses on the fact that the flight was delayed

So:

• Chuyến bay nối chuyến đến chậm = the connecting flight arrived late
• Chuyến bay nối chuyến bị chậm = the connecting flight was delayed

In English these can be very close in meaning, but Vietnamese is highlighting a slightly different angle.

Yes. If you say:

• Chuyến bay đến chậm

that simply means The flight arrived late or The flight is late arriving, depending on context.

Adding nối chuyến just gives more information about what kind of flight it is: a connecting one.