A passenger seat system (10) comprises a backrest (12) as well as a seat (14), which comprises a first sub-portion (16) having a first surface (18) and a second, opposite surface (20) to the first surface (18) as well as a second sub-portion (22) having a first surface (24) and a second, opposite surface (26) to the first surface (24). The first sub-portion (16) and the second sub-portion (22) are movable relative to one another in order to adjust the seat (14) between a first and a second operating position. In the first operating position of the seat (14) the first sub-portion (16) and the second sub-portion (22) are positioned in relation to the backrest (12) one behind the other in such a way that the first surface (18) of the first sub-portion (16) and the first surface (24) of the second sub-portion (22) form a usable total seat surface. In the second operating position of the seat (14) the first sub-portion (16) and the second sub-portion (22) are positioned in relation to the backrest (12) one above the other in such a way that one of the surfaces (18, 20) of the first sub-portion (16) or the first surface (24) of the second sub-portion (22) forms a usable partial seat surface.