Aircraft Seat Widths AircraftAisle Seat WidthMiddle Seat WidthWindow Seat Width 319 17.4"-18" 17.8"-19.1" 17.1"-18" 320 17.4"-18" 17.8"-19.1" 17.1"-18" 321 16.7"-18" 16.5"-19.1" 16.5"-18"