A highly contentious and dividing topic that generates various reasons and viewpoints that support both the reasons for and against having at least 2 persons in the cockpit at all times. On one hand many believe that there should always be the presence of two people in the cockpit at any one time, with at least only one of them being an on-duty pilot during cruise/ non-critical phases. On the contrary, there are supporters of there only having to be one pilot in the cockpit at any one time, during cruise/non-critical phases of flight and there are even some calling for single-pilot operations full stop.