A seat in a vehicle includes a seatback and an airbag assembly. The seatback includes a frame and an upholstery supported by the frame. The upholstery includes an inner surface facing the frame. The airbag assembly is fixed to the inner surface of the upholstery. The airbag assembly of the seat provides coverage of the seatback so as to absorb impact energy for knees and a head of an occupant seated behind the seat.