From the Linear Flight Planning page:
https://support.dronesmadeeasy.com/hc/en-us/articles/115000167986-Linear-Flight-Planning
"By swiping left or right on the top status bar, the number of passes in a linear mission can be reduced or increased. The minimum number of passes is 1 and the maximum number is 15. These passes are laid out according to the overlap settings just as any other mapping mission."

