Depois do atraso, os voos voltaram a sair no horário normal.

Because depois is normally followed by the preposition de when it means after.

So the structure is:

• depois de = after
• o atraso = the delay

When de comes before o, they contract:

• de + o = do

So:

• depois do atraso = after the delay

You could think of it as literally after of-the delay, even though that sounds unnatural in English.

Atraso means delay.

In this sentence, it refers to some disruption that caused the flights not to leave at their usual time. It is a very common noun in Portuguese:

• houve um atraso = there was a delay
• o voo teve atraso = the flight had a delay
• por causa do atraso = because of the delay

So depois do atraso means after the delay or once the delay was over.

Os is the masculine plural definite article, meaning the.

• o voo = the flight
• os voos = the flights

So os voos means the flights.

Also, note the spelling:

• singular: voo
• plural: voos

In modern Portuguese spelling, voos has no accent mark.

Voltaram a sair means started leaving again, went back to departing, or resumed departures.

This is different from simply saíram, which just means left/departed.

The pattern is:

• voltar a + infinitive

This often means to do something again or to resume doing something.

Examples:

• voltou a chover = it started raining again
• voltei a estudar = I went back to studying / started studying again
• os voos voltaram a sair = the flights started departing again

So the sentence emphasizes that there had been an interruption, and then normal departures resumed.

That a is part of the structure voltar a + infinitive.

It is not the article a meaning the. It is a preposition that links voltar to the infinitive verb.

So:

• voltar a fazer algo = to do something again / to resume doing something

In this sentence:

• voltaram a sair = they resumed departing

This is a very common pattern in Portuguese.

Yes. Sair normally means to leave, to go out, or to depart.

With transportation, especially flights, buses, and trains, Portuguese often uses sair where English might say leave or depart.

Examples:

• O voo sai às 10h. = The flight leaves at 10.
• O ônibus saiu atrasado. = The bus left late.
• Quando o trem vai sair? = When is the train going to leave?

So os voos voltaram a sair is a natural way to say that flights resumed departing.

No horário normal means at the normal time or on the usual schedule.

Breakdown:

• em = in / at / on
• o horário normal = the normal time / usual schedule

And again there is a contraction:

• em + o = no

So:

• no horário normal = at the normal time

Depending on context, horário can mean:

• a specific time
• a scheduled time
• a timetable/schedule

Here it refers to the usual departure schedule.

Yes, depending on context.

Horário can mean:

• time
• scheduled time
• timetable
• schedule

In this sentence, no horário normal could be understood as:

• at the normal time
• on the usual schedule
• according to the normal timetable

English may choose different translations, but the Portuguese expression is very natural.

Yes. Portuguese often places a time expression at the beginning of the sentence, just like English can.

So:

• Depois do atraso, os voos voltaram a sair no horário normal.

is very natural.

You could also say:

• Os voos voltaram a sair no horário normal depois do atraso.

That is also grammatical and natural. The version with Depois do atraso first gives a little more emphasis to the timing/background: first there was a delay, then normal departures resumed.

Because the subject is os voos, which is plural.

• o voo voltou = the flight resumed / went back
• os voos voltaram = the flights resumed / went back

Portuguese verbs agree with the subject in number and person, so the plural subject requires the plural verb form voltaram.

Yes, in many contexts you could.

• sair = to leave / depart
• decolar = to take off

The difference is subtle:

• os voos voltaram a sair focuses on flights leaving according to schedule
• os voos voltaram a decolar focuses more specifically on planes taking off

In airport or scheduling language, sair is very common and natural for departures. Decolar is also correct, but it emphasizes the physical takeoff more than the scheduled departure.

Very often, yes.

Common patterns include:

• depois de + noun

  • depois do atraso = after the delay
  • depois da aula = after class

• depois de + infinitive

  • depois de comer = after eating
  • depois de chegar = after arriving

There is also depois que, which is used before a clause with a conjugated verb:

• depois que o voo saiu = after the flight left

So in this sentence, since atraso is a noun, depois de is exactly what you would expect.

Yes, that is a good nuance to notice.

Literally, no horário normal refers to the normal time/schedule, but in context it often suggests a broader idea: operations returned to normal.

So the sentence does not just mean that flights departed once; it suggests that after the delay, departures were happening again according to the usual schedule.

That is why the combination of:

• voltaram a sair = resumed departing
• no horário normal = on the normal schedule

creates a strong sense of things getting back to normal.