Learn Spanish (Spain): Se buscan azafatas que hablen inglés. - Flight attendants who speak English wanted.

Because the specific flight attendants haven't been found yet. When you are looking for someone who fits a certain description, but you don't know who they are or if they even exist, Spanish uses the subjunctive in the que clause. If they were looking for specific people they already knew, they would use the indicative hablan.

Why use Se buscan here instead of just Buscan?

This is the passive se structure, which is very common in Spanish job adverts and signs. It translates literally to 'Flight attendants are sought.' It is used to focus on what is needed rather than who is doing the looking.

Why is the verb buscan plural?

In passive se sentences, the verb must agree with the noun being acted upon. Because the advert is looking for multiple azafatas (plural), the verb must be the plural buscan. If they only wanted one flight attendant, it would be Se busca azafata.

Why isn't the word inglés capitalized?

Unlike in English, Spanish does not capitalize the names of languages, nationalities, or months unless they are the very first word of a sentence.