Final answer:
The correct pronoun for the sentence is 'their', which refers to a group of people who want to travel.
Step-by-step explanation:
The correct pronoun to fill in the blank is their. The pronoun 'their' is used to refer to a group of people. In this sentence, it is used to refer to the people who want to travel. For example, you can rewrite the sentence as 'There are many people who want to travel.'
Learn more about Using pronouns correctly