Después de una escala corta, volvimos a subir al avión.

Después often needs de when it is followed by a noun or noun phrase.

• después de una escala corta = after a short stopover
• después by itself usually means afterwards / later

So:

• Después de una escala corta... = After a short stopover...
• Después, volvimos a subir al avión. = Afterwards, we boarded the plane again.

Both are correct, but they mean slightly different things structurally.

In travel language, escala means a stopover, layover, or stop during a journey.

So here una escala corta means a short stop between flights or between parts of the same journey.

Be careful: escala has other meanings too, such as:

• scale on a map
• scale in music
• stairway in some contexts

But in an airport/travel sentence, escala usually means layover/stopover.

In Spanish, adjectives usually come after the noun.

So:

• una escala corta = a short stopover

This is the normal word order. Putting the adjective before the noun is sometimes possible in Spanish, but it often changes the tone or emphasis. For a simple factual description, escala corta is the natural choice.

Volvimos is the preterite form of volver for nosotros.

• infinitive: volver
• preterite: yo volví, tú volviste, él/ella volvió, nosotros volvimos...

Here it means we did it again / we went back and did it, referring to a completed action in the past.

So volvimos a subir means we boarded again or more literally we went back to getting on.

Because volver a + infinitive means to do something again.

• subimos al avión = we boarded the plane / we got on the plane
• volvimos a subir al avión = we boarded the plane again

So volver a adds the idea of repetition.

This is a very common Spanish structure:

• Volví a leer el mensaje. = I read the message again.
• Volvieron a llamar. = They called again.

Because the structure is:

volver a + infinitive

So:

• volvimos a subir
• not volvimos subir

That a is required in this pattern.

It works like this in general:

• voy a salir
• volvió a intentarlo
• hemos vuelto a verlo

Whenever volver means to do again, it is normally followed by a + infinitive.

Because subir al avión means to get on / board the plane.

Here, subir is about movement onto the plane. Spanish uses a for movement toward or onto something:

• subir al tren
• subir al autobús
• subir al avión

By contrast, en el avión usually refers to being in/on the plane, not the action of boarding it.

So:

• subir al avión = to board the plane
• estar en el avión = to be on the plane

Because a + el contracts to al in Spanish.

So:

• a + el avión → al avión

This contraction is mandatory.

The same happens with de + el:

• del avión = from the plane

But note that this does not happen with la:

• a la estación
• de la estación

Yes, literally subir means to go up or to climb, but in transport contexts it often means to get on / board.

So in many cases, the most natural English translation is not go up, but:

• board the plane
• get on the plane

Spanish often uses subir where English uses a transport-specific verb like board.

Not naturally in this context.

The standard and idiomatic way to say did it again is:

• volver a + infinitive

So volvimos a subir al avión is the best choice.

Regresar means to return/go back, but it is not normally used in the same way as volver a + infinitive to mean repetition of an action.

A learner might guess regresamos a subir, but native speakers would strongly prefer volvimos a subir.

Because that opening phrase is an introductory time expression.

• Después de una escala corta, volvimos a subir al avión.

The comma helps separate the background information from the main clause. In Spanish, this kind of comma is common and natural, especially in careful writing.

You may sometimes see similar short introductory phrases without a comma, but with a phrase like this, the comma is very normal.

Yes, that would also be grammatical.

• volvimos a subir al avión
• subimos otra vez al avión

Both can mean we boarded the plane again.

The version with volver a + infinitive is often slightly more idiomatic and elegant in Spanish when talking about repeating an action.

So both work, but volvimos a subir is especially common and natural.

By itself, yes:

• volvimos can mean we returned / came back

But in this sentence, the structure volvimos a subir clearly means we got on again or we boarded again.

That is because:

• volver alone = to return
• volver a + infinitive = to do something again

So the a + subir removes the ambiguity.