Learn German: Wir fliegen nach Spanien, oder wir bleiben hier. - We are flying to Spain, or we are staying here.

The verb is in position 2! The trick is the word oder (or). It is a coordinating conjunction, which means it sits in "position 0" and doesn't count towards the word order. So, in the second half of the sentence, wir is position 1, and bleiben takes position 2.

Would the sentence still be correct if I dropped the second wir?

Yes! Because the subject (wir) is the exact same in both halves of the sentence, you can leave it out after oder. You could just say: Wir fliegen nach Spanien, oder bleiben hier.

Is the comma before oder required here?

When oder connects two complete phrases that both have their own subject and verb, a comma is optional. You will often see it included to make the sentence easier to read, but it is not strictly required like it is with aber (but) or denn (because).

Why do we use nach for "to Spain" instead of another word for "to" like zu?

In German, when you travel to a geographical place that doesn't use a "the" before its name (like most cities, countries, and continents), you always use nach. So it is nach Spanien, just like nach Berlin or nach Europa.