In today's day and age, it is common to have gaps in employment. There are often various reasons why someone may have a gap including becoming a stay-at-home parent, job loss, redundancy, and many other reasons. The honest approach is the best approach. Airbus interviewers will more than likely ask a question similar to this if they identify any gaps in employment. You can simply let the interviewer know the reason (if you feel comfortable) and why depending on what the situation was.