The invention relates to a seat unit including a seat, at least one surrounding element associated with the seat, and a noise attenuation panel fixed to one face of the surrounding element. The noise attenuation panel can include a soft trim cover, and a support plate comprising at least one sound-permeable portion provided with at least one through hole. The support plate can be arranged such that there is an empty space between said sound-permeable portion and the face of the surrounding element of the seat.