Be honest in your answer. If you do not want to travel at all and the job requires travel, it is not a good fit. If you can travel but not overnight, not on certain weekends, or only with a certain amount of notice, let the interviewer know.

"I know the job posting said travel would be limited but could be 5-10% of the job. I would be more than happy to travel for employee meetings and am always excited about the opportunity to attend a seminar or conference or do training in the field. If the travel is during the day only and does not involve an overnight stay, I can travel any time with limited notice. If it would require being gone overnight or for several days/nights, I would need to have at least a week of notice to make sure I could schedule the necessary childcare."