This is a tricky question. Before you start to think about your answer, you should understand whether there actually will be any business trips in the company (job description should help you with the task).
When we were interviewing women for secretary positions, we gave them this question every single time–doesn’t matter if there were any business trips or not.
If the candidate got very excited about the question (saying how they would love to travel and enjoy this aspect of a job), in most cases we would not hire them (especially if they were not supposed to go to any business trips with their future bosses).
Why did we not hire them? Simply because they would not be happy in their job. They expected something more than the position would offer. But we heard all kinds of interview answers…
Some job applicants didn’t like the question, considering it inappropriate. They imagined everything one can imagine when hearing “accompanying boss on a business trip”.
Needless to say, we did not hire these candidates, doesn’t matter if business trips belonged to their job or not. It is a common thing to accompany someone on a business trip, and it is a job – nothing else, nothing more, nothing less.
Flexibility in question
Your answer to this question says a lot about your flexibility. If you say you can not accompany the boss, because you need to be at home at 4pm every day (for example because you have children), it is a clear sign of your inflexibility.
It doesn’t necessarily have to be a problem–sometimes the working hours are steady, and you can leave your job exactly at three each afternoon. But in some cases it can be a problem.
All in all, this is not an easy question to answer, especially when you have no idea whether the business trips belong to the job, and what the working hours are.
I suggest you to pick a neutral answer. Do not get too excited about the proposition of traveling. Just say that you would not mind accompanying boss on trips, if it was a part of your job. Later on, when you already have the job, you can refuse accompanying them.
As I said before, you do not necessarily have to stick to the promises you made in your interview. Unless it is in your employment contract, you can refuse to travel.
I did not think about this aspect of the job. However, if it was necessary to accompany them, and if my professional assistance was important during the trip, I would not mind going with them.