Gee, where did all the PMUA cheerleaders go? PMCO had a fairly young fleet; the PMUA fleet did a good job of pushing that average way way up.
Originally Posted by
JC1120
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.
More frequent MX issues on older planes, too. Allegiant Air suffers heavily from this with their mad dogs. UA's 744 dispatch reliability is atrocious, as well.