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

Because de + o normally contracts to do in Portuguese.

• depois de = after
• o atraso = the delay
• depois do atraso = after the delay

This kind of contraction is very common:

• de + a = da
• em + o = no
• em + a = na

So depois do atraso is the natural standard form.

Atraso means delay or lateness.

In this sentence, it refers to a delay affecting the flights. It does not necessarily mean a person being late; it can also refer to delayed transportation, delayed plans, delayed service, and so on.

Examples:

• O voo teve atraso. = The flight had a delay.
• Cheguei com atraso. = I arrived late.

Here, o atraso is understood as the delay that happened before the flights returned to normal.

Portuguese often uses the definite article where English would not.

So os voos literally means the flights, but in context it can sound perfectly natural even when English would simply say flights.

It suggests we are talking about a specific set of flights already known from the situation, such as the flights affected by the delay.

Also, note the spelling:

• Modern Brazilian Portuguese writes voos
• Older spelling was vôos

The accent was removed by the spelling reform.

Literally, it means returned to leave, but the natural meaning is started leaving again or resumed departing.

The structure is:

• voltar a + infinitive

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

Examples:

• Voltei a estudar. = I started studying again.
• Ela voltou a trabalhar. = She went back to work / started working again.
• Os voos voltaram a sair. = The flights started departing again.

So this is a very useful pattern to learn.

Yes, and that is exactly why it works here.

For flights, sair is commonly used to mean to leave or to depart, especially in the sense of scheduled departure.

So:

• O voo sai às 10h. = The flight leaves at 10.
• Os voos voltaram a sair. = The flights started departing again.

If you wanted to focus on the physical act of taking off into the air, you might use decolar:

• O avião decolou. = The plane took off.

But in this sentence, sair fits well because the idea is about departure times and schedule, not the mechanics of takeoff.

Voltaram is the preterite form of voltar, used for a completed event in the past.

The sentence describes something that happened after the delay:

• first there was a delay
• then the flights resumed departing

That sequence is seen as a completed event, so the preterite is the normal choice.

Compare:

• Os voos voltaram a sair no horário normal. = The flights resumed departing on time.
  Completed past event.
• Os voos voltavam a sair no horário normal. = The flights would resume departing on time / used to resume departing on time.
  This would suggest a repeated or background past situation, which is not the meaning here.

It means at the normal time or on the normal schedule.

Here:

• em + o = no
• horário = schedule / time slot / scheduled time
• normal = normal / usual

So no horário normal literally means in the normal schedule/time.

In context, it means the flights were departing according to their usual or expected schedule again.

This does not necessarily mean exactly on time in the abstract sense; it means that operations returned to the regular timetable.

Usually, no horário normal is much more natural here.

Why?

• horário is commonly used for schedules, timetables, and set departure times.
• tempo usually refers more to time in general, duration, or even weather, depending on context.

So for flights, buses, classes, stores, etc., horário is the right word when talking about schedule.

Natural:

• O voo saiu no horário normal.
• A loja voltou ao horário normal.

Less natural here:

• no tempo normal

Both can suggest again, but they are not exactly the same.

• voltaram a sair = resumed departing / started departing again after an interruption
• saíram de novo = departed again

In this sentence, voltaram a sair is better because it clearly suggests that the delay interrupted normal departures, and then departures resumed.

So:

• Depois do atraso, os voos voltaram a sair no horário normal.
  After the delay, flights resumed departing on their normal schedule.

• Depois do atraso, os voos saíram de novo.
  After the delay, the flights left again.

The second version is grammatical, but it does not express the idea of resumption after interruption as clearly.

Yes. Portuguese word order is fairly flexible, especially with time expressions like depois do atraso.

For example:

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

Both are correct.

The version with Depois do atraso at the beginning helps set the scene first, which is very common in both Portuguese and English.

A very natural translation would be:

• After the delay, flights resumed departing on schedule.
• After the delay, the flights went back to departing on their normal schedule.
• After the delay, flights were departing on time again.

The best version depends on context, but the important idea is:

1. there was a delay
2. normal departures resumed afterward

In Brazilian Portuguese, voos is pronounced roughly like VOH-os, with two vowel sounds in sequence.

It is not a single long vowel. You can think of it as:

• vo-os

This happens because the word comes from voo in the singular and voos in the plural.

So:

• voo = flight
• voos = flights

Many learners want to compress it too much, but it helps to keep both vowel sounds audible.