Originally Posted by
zrs70
But in terms of comfort, it's a non-issue.
They can retrofit interiors to modern designs, but in general, older planes tend to have less sound insulation and older fuselage/engine designs that can lead to higher noise levels. Also, depending on the refurbishment, the older planes may not have HEPA and UV air filtration systems. In the case of the A380/787, there are actually higher cabin humidity levels as well.