Qual é o horário do voo?

In this sentence, qual means what in the sense of which one / what is.

Portuguese often uses qual when asking for a specific piece of identifying information:

• Qual é o seu nome? = What is your name?
• Qual é o horário do voo? = What is the flight time / What time is the flight?

So even though English uses what, Portuguese often uses qual é in this kind of question.

Yes. É is the he/she/it form of ser (to be) in the present tense.

So the structure is literally:

• Qual = what / which
• é = is
• o horário do voo = the flight’s time / the time of the flight

A very literal translation would be:

• What is the time of the flight?

Not exactly.

• hora usually means hour or time in a general sense
• horário often means schedule, time slot, scheduled time

In this sentence, o horário do voo refers to the flight’s scheduled time, not just the abstract concept of time.

Compare:

• Que horas são? = What time is it?
• Qual é o horário do voo? = What is the flight’s scheduled time?

Portuguese uses definite articles much more often than English.

So o horário literally means the time / the schedule, and that sounds natural in Portuguese. In English, we might leave out the in some contexts, but in Portuguese the article is usually kept.

That is why:

• Qual é o horário do voo? sounds natural
• dropping o would usually sound incomplete or unnatural here

Do is a contraction of:

• de = of
• o = the

So:

• de + o = do

That means:

• o horário do voo = the time of the flight

This kind of contraction is very common in Portuguese:

• de + a = da
• de + os = dos
• de + as = das

Voo is the modern spelling in Portuguese. It comes from the verb voar (to fly) and means flight.

Older spelling used to have an accent in some related forms, but under current spelling rules:

• voo = flight
• no accent mark

So voo is correct in modern Brazilian Portuguese.

In Brazilian Portuguese, voo is pronounced roughly like VOH-oh, in two vowel sounds that flow together.

A simple approximation for English speakers:

• voo ≈ VOH-oo, but very smooth and short

The sentence as a whole is approximately:

• kwal eh oo oh-RAH-ryoo doh VOH-oh

That said, pronunciation varies a bit by region.

Yes, that is also common and very natural in Brazilian Portuguese.

Compare:

• Qual é o horário do voo? = What is the flight time? / What is the scheduled time of the flight?
• Que horas é o voo? = What time is the flight?

The second version is a bit more direct and conversational. The first one sounds slightly more formal or more focused on the scheduled time.

The given word order is the most standard and natural:

• Qual é o horário do voo?

You may also hear:

• O voo é qual horário? — understandable, but not the normal way to ask
• Qual o horário do voo? — very common in speech and informal writing

So in Brazilian Portuguese, both of these are common:

• Qual é o horário do voo?
• Qual o horário do voo?

The version with é is a little more complete and textbook-standard.

Both can relate to what, but they are not always interchangeable.

Very roughly:

• qual is often used for identifying a specific thing from a set, or in what is... type questions
• que is often used directly before a noun

Examples:

• Qual é o problema? = What is the problem?
• Que problema é esse? = What problem is that?

In your sentence, qual é o horário do voo? is the natural choice. A version with que would usually be expressed differently, such as:

• A que horas é o voo? = At what time is the flight?

Yes, very important.

There are two accents here:

• é — this is the verb is
• horário — the accent shows stress placement

Without the accent in é, you would get e, which means and

• é = is
• e = and

And in horário, the accent helps show the stressed syllable:

• ho-RÁ-rio

So accents are not optional; they can change meaning and pronunciation.

Yes, but often alongside simpler everyday alternatives.

Very natural real-life options include:

• Qual é o horário do voo?
• Que horas é o voo?
• A que horas sai o voo? = What time does the flight leave?
• A que horas chega o voo? = What time does the flight arrive?

So your sentence is correct and natural, especially when asking generally about the flight’s scheduled time.