Originally Posted by
DaveReidUK
Early B741s/B742s were built with 3 windows, later ones with 10.
In addition, some airlines (including BA in the late 1970s) modified their early aircraft, which involved replacing the skin panels as can be seen on this NW B741:
https://www.airliners.net/photo/Nort...ng-747-151/635
I always thought these additional windows were added by simply ‘punching them out’
Instead it sounds like you’re saying the skin panels encompassing them were entirely removed and replaced with new ones incorporating the additional windows ?