Answer:
The correct direct object pronouns that fill the blanks are:
1. Los viajeros compran los pasajes. Ellos los compran.
2. La viajera confirma la reservación. Ella la confirma.
3. El empleado tiene las llaves. Él las tiene.
4. Yo escribo una carta. Yo la escribo.
5. Alejandra pierde el equipaje en el aeropuerto. Ella lo pierde.
Step-by-step explanation:
In Spanish, some direct object pronouns are similar to the articles, in the first three sentences I underlined the articles because those are the same word that the direct object in the contract sentence; in the fourth sentence, the article is undefined "una" but continues referencing to a female object, by this reason, the direct object pronoun is "la" and the last sentence, the subject "el equipaje" is a male object, then its direct object pronoun is "lo".