Rather than being too focused on yourself, why not give a moments thought to why the interviewer is asking the question.
Unless you are really going to say something that is likely to shock the interviewer it may well be that the answer doesn't matter at all. This is an interview and having made it this far, the interviewer wants to pose a limited range of questions that both keep you within your own comfort zone, and also perhaps take you outside of it in order to see how you respond rather than with any great focus on the content of your reply.
For example. A constituent part of this job is communicating with your passengers. Somebody who can provide a relaxed confident reply to a question about themselves, should have little difficulty in adapting to a communication task that also requires a confident relaxed style. The interviewer is likely to note how you respond to a question that you really should be able to answer. There is no particular right or wrong answer, but there is often a very definite character, manner and style that comes through when somebody is giving an honest answer about their own aspirations, achievements or life.
Again with communication at the forefront, how does somebody deal with a difficult question or one that is likely to take them outside of their comfort zone. Does the reply seem thoughtful, honest, considered, and in keeping with the general characteristics of that individual candidate. Does it sound rehearsed, is there a shift or change in the temperament of the responses.
An example of this might be, "why should we offer you the vacancy in preference to the other candidates in the waiting room?" Of course the strong temptation here is to become instantly competitive and proffer every thing you can think of that might project your keenness for the job. However this is very much a "teamwork" profession, and your answer to this question can quickly reveal potential flaws in that particular quality.
Any interviewer is looking for the best candidates to fill the vacancy. That "best" is a combination of perceptions and presentation. Two candidates can give totally dissimilar answers to non-technical questions, and both be successful at interview.
You will often see interviewers making notes and ticking boxes. This is quite difficult to do whilst listening to a reply. Very often it isn't the content of the reply being given that is being marked, but the general manner, demeanor, and attitude of the candidate. Although the situation doesn't really lend itself to being relaxed, the interviewers are well aware of that. Be yourself, be honest, be prepared and be confident. This is your opportunity to sell yourself. The buyer is looking for a reliable and honest product.