A pair of pants including a fly that can be opened and closed via a bi-directional zipper that extends from a top end proximal to an upper terminus of the pants to a bottom end at the crotch point of the pants. The zipper includes a top slider and a bottom slider that travel on a common set of zipper teeth. The top slider separates the zipper teeth when moved in a direction away from the top end toward the bottom end and closes the zipper teeth when moved in the opposite direction. The bottom slider separates the zipper teeth when moved in a direction toward the top end and away from the bottom end and closes the zipper teeth when moved in the opposite direction. The pants allow a wearer to excrete urine while in a sitting position, particularly such as when the wearer is operating an aircraft.