Learn Hardcore Spanish (Latin America): Mi amiga iba a viajar hoy, pero canceló el vuelo por la tormenta. - My friend was going to travel today, but she canceled the flight because of the storm.

So iba a viajar literally = “was going to travel.”
It describes a planned action in the past that is not presented as completed (and here we know it didn’t happen, because she canceled the flight).

Why is iba a viajar used instead of va a viajar (“is going to travel”) or viajará (“will travel”)?

Va a viajar hoy = “She is going to travel today” (a plan in the present or near future).
Viajará hoy = “She will travel today” (future tense, often more formal or neutral prediction).
Iba a viajar hoy = “She was going to travel today” (a plan viewed from the past).

In the sentence, the speaker is talking about a plan that existed earlier (before now) and that was affected (canceled) by the storm. That’s why the imperfect (iba a viajar) is the correct choice.

Could I say Mi amiga fue a viajar hoy to mean the same thing?

No, that would sound incorrect or at least very strange in normal Spanish.

Fue is the preterite of ir and usually means “went” (a completed action of going somewhere), not “was going to” as in a plan.
Fue a viajar would literally be “she went to travel,” which doesn’t match the idea of a plan that was canceled.

To express an intended or planned action in the past (especially one that didn’t happen), Spanish uses iba a + infinitive, not fue a + infinitive:

Mi amiga iba a viajar hoy, pero… = “My friend was going to travel today, but…” ✅

Why do we need the a in iba a viajar? Can I say iba viajar?

You must use a here. The construction is:

ir (in any tense) + a + infinitive

Examples:

Va a viajar – She is going to travel
Iba a viajar – She was going to travel
Vamos a viajar – We are going to travel

Saying iba viajar (without a) is incorrect in this meaning.
Without the a, it just doesn’t form the “going to do X” future/intended-action structure.

Why is there no ella (she) before iba? Could I say Mi amiga ella iba a viajar…?

Spanish usually drops subject pronouns (yo, tú, él, ella, etc.) when the subject is clear from context or from the verb ending.

Iba (imperfect of ir) already tells us the subject is he/she/it/you-formal.
We also have mi amiga (“my [female] friend”) right before it, so the subject is totally clear.

You could say Ella iba a viajar hoy, but combining both:

Mi amiga ella iba a viajar hoy is normally redundant and unnatural.
Native speakers would just say:
Mi amiga iba a viajar hoy… ✅
or, in some contexts:
Ella iba a viajar hoy… ✅

Why is it mi amiga and not mi amigo? What does that tell us?

Amigo/amiga change gender:

amigo = (male) friend
amiga = (female) friend

The possessive mi doesn’t change form for gender (only for number: mi vs mis):

mi amigo – my (male) friend
mi amiga – my (female) friend
mis amigos / mis amigas – my friends

So mi amiga tells us the friend is female. That’s why in English we translate “she canceled the flight.”

What does canceló mean exactly, and what tense is it? Why not cancelaba?

Canceló is the preterite (simple past) of cancelar, 3rd person singular: “she canceled.”

It refers to a single, completed action in the past.

Using cancelaba (imperfect) would change the meaning:

cancelaba = she was canceling / she used to cancel / she would cancel (habitually)

In this sentence, the cancellation is a one-time, completed event: she canceled the flight at some point. So:

canceló el vuelo – “she canceled the flight” ✅
cancelaba el vuelo – sounds like an ongoing or repeated action (not what we want here) ❌

Why is it el vuelo (“the flight”) and not su vuelo (“her flight”) or just vuelo?

All three are possible, but they sound a bit different:

canceló el vuelo
- Literally: “she canceled the flight.”
- Very natural in Spanish when the context makes it obvious which flight we’re talking about (the one she was going to take).
- Spanish often uses the definite article el/la more freely than English uses “the.”
canceló su vuelo
- “She canceled her flight.”
- Also correct, and maybe a bit closer to typical English phrasing.
- Slightly more explicit that it’s her booking.
canceló vuelo (no article, no possessive)
- Sounds incomplete or unnatural in this context.
- You’d normally use an article (el/un) or a possessive (su) with vuelo here.

So el vuelo is perfectly normal and idiomatic Spanish.

What does por la tormenta mean here, and why not porque de la tormenta?

Por la tormenta means “because of the storm” or “due to the storm.”

por here introduces a cause/reason:
- canceló el vuelo por la tormenta = “she canceled the flight because of the storm.”

Porque de la tormenta is incorrect.
In Spanish:

porque = “because” (conjunction, followed by a clause)
- Canceló el vuelo porque había una tormenta.
  – “She canceled the flight because there was a storm.”
por / a causa de / debido a = “because of / due to” (followed by a noun)

So:

por la tormenta ✅
porque había una tormenta ✅
porque de la tormenta ❌

Why is it por la tormenta and not para la tormenta?

Por and para both translate to “for” in some contexts, but they’re used differently.

Here we talk about a cause/reason, so we must use por:

por la tormenta = because of the storm (the storm is the cause of canceling).

Para usually expresses purpose, destination, or goal, not cause:

para la tormenta would sound like “for the storm” in the sense of “intended for the storm,” which makes no sense here.

So in expressions of cause like this, choose por, not para:

Lo hizo por dinero. – He did it because of money / for money.
Canceló el vuelo por la tormenta. – She canceled the flight because of the storm.

Why is viajar used and not viaje? What’s the difference?

viajar is a verb = “to travel.”
viaje is a noun = “trip / journey.”

The structure iba a + infinitive demands a verb in the infinitive, so we need viajar:

iba a viajar – “was going to travel” ✅

Using viaje there would be ungrammatical:

iba a viaje ❌

You can use viaje in other structures:

Iba a hacer un viaje hoy. – She was going to take a trip today. ✅
Tenía un viaje hoy. – She had a trip today. ✅

But after iba a, you must use a verb (viajar, salir, volar, etc.), not the noun viaje.