Seating groups for passengers, for example in an aircraft cabin, are equipped with several seats having seat components supported on a support base on which the seat components, especially the seat sections are laterally slideable to make the seats wider when a passenger sits on a seat or narrower when a passenger is not sitting on a seat. The seat widening or narrowing is accomplished in several ways, for example, with the aid of a grooved shaft that operates as a spindle when turned by tilting a seat component, or by springs that vault upwardly when not loaded and spread when a passenger sits on a seat supported by the springs. The grooved shaft can be operated for example by an armrest or a seat section.