Originally Posted by
DaveReidUK
"A bigger cross-section to improve weight" ?
Yes, at some point cross section starts to help. Imagine a 2-2 cross section e.g. CRJ, still with 240 seats / luggage space.
It becomes extremely long and bending moments around the middle of the fuselage require lots of material (additional weight) to keep it stiff and strong enough.
That also become a factor when 2-3 or 3-3 cross section are stretched real far.
https://www.aircharter.com.hk/aircra.../boeing757-300