Originally Posted by
3Cforme
Delta's active A320s all came from Northwest and were introduced to service between 1990 and 1999. Both Delta and Northwest had 757-200s. The active fleet was introduced to service between 1990 and 2005.
https://www.planespotters.net/airline/Delta-Air-Lines
Aircraft manufacturers had figured out temperature control in the 1960s. Turbulence is largely a function of wing loading, not aircraft age. Passengers may note the age of interiors (seats, bins, AVOD, service units - the overhead lights and air vents). They will not note the age of engines.
Broadly true, but there are legitimate differences in terms of cabin noise - modern engines themselves are quieter and the cabin noise insulation is better.
In addition, turbulence is a bit more nuanced than that. Modern aircraft (I know the 787 and A380 do, but it may be present in others now) have gust attenuation capabilities that essentially detect a gust as soon as it reaches the plane and proactively adjusts the whole plane to it in advance of it impacting the whole plane (as opposed to "old" methods which are more reactive to the effects of the gust itself). Further, modern planes with higher composite amounts in the wings (namely the A350 and 787) reduce turbulence because the wings "flap" more and absorb more of the energy before it reaches the main portion of the plane.
That said, the core of all of the major narrowbody airframes (737, 320 series) haven't changed much in the past 20 years so I don't think there would be much of a difference for OP - especially when comparing the 757 to Delta's other offerings (aging A320s and last generation 737s).