In large organisations, an interview with the senior executive happens when you have already been given a green signal by your hiring manager. The fact that you are meeting the senior executive usually means that you are 90% “in”.
In very small companies, the senior executive or the owner plays a bigger role in evaluating the candidate. If this is your case then treat it as an interview with hiring manager.
Warren Buffet said he looks for three attributes – intelligence, integrity and energy – in the candidates he interviews. Identify a few succes stories which highlight not only your hard skills but also these three attributes.