$\begingroup$ @peterh all the questions here about helicopters or planes or gliders or ballons on Mars and Venus would then have to be considered for closure as off-topic by the same logic. I think as long as this question is specifically about atmospheric flight on Mars, a planet were so far as we know, no atmospheric flight has ever happened, it is on-topic an d should remain open. $\endgroup$ – uhoh May 28 '19 at 0:48