Because of the aircraft's shape, the seating layout would be theatre-style instead of tubular. This imposes inherent limits on the number of exit doors.[12][13] It has been suggested that BWB interiors would be windowless,[14] more recent information shows that windows may be positioned differently but involve the same weight penalties as a conventional aircraft.[15] It has been suggested that passengers at the edges of the cabin may feel uncomfortable during wing roll[14] however, passengers in large conventional aircraft like the 777 are equally susceptible to dutch roll.[15] The centre wingbox needs to be tall to be used as a passenger cabin, requiring a larger wing span to balance out.[16] A BWB has more empty weight for a given payload, and may not be economical for short missions of around four or fewer hours.[16] A larger wing span may be incompatible with some airport infrastructure, requiring folding wings similar to the Boeing777X. It is more expensive to modify the design to create differently-sized variants compared to a conventional fuselage and wing which can be stretched or shrunk easily.[16]