Seat extension with modular length, unit comprising a seat extension and passenger cabin

Cabin of a vehicle for transporting passengers comprising a plurality of units, each unit comprising a seat and a modular seat extension arranged staggered in said plurality of units, wherein each modular seat extension comprises a shell comprising a front bottom and a rear opening determined by a hollow volume open towards the rear and, a footrest area inside said hollow volume wherein:

• the shell of each one of the seat extensions comprises an invariant portion and a modular portion located in front of said invariant portion, said modular portion making it possible during the fastening thereof to the invariant portion, to obtain a seat extension with a length that can be modified between the rear opening and the front bottom of the shell,
• and in that a passage width L towards the aisle between the seats and the seat extensions of said plurality of units is maintained constant during the use of the seat extensions by the passengers intended to travel in said cabin.