So this person is going to join in on a holiday trip with children under five??? You don’t think having a stranger along wouldn’t skew the results?
Whoever taught you to this should have their teaching license revoked. A clear objective is a necessity, not an option. To create that objective, have you narrowed your scope?
Holiday travel with children under five.
By plane, train or automobile?
With family, friends or other?
What is the duration, 1 day, 1 weekend, 1 week?
Infant or toddler?
How many children?
First time traveling with child?
Staying in home or hotel?
That is what comes to mind without any thought. With an hour, I’m sure 100 more questions would come to mind. All good interviews are structured and well planned. They may not appear so, but they are well researched prior to the interview. Winging it will produce the bad data I mentioned.
Have an objective. Have someone with experience review your objective. Determine your target respondent. Have someone with experience review your choices. Create a script. Have someone with experience review your script. If it all possible, do dry runs of your script with that someone with experience. Don’t use the person who thought an unstructured interview was a good idea.