one guy’s opinion — I was never a “road warrior” in the classic sense, although I had more than a few months of weekly travel pretty much every year from 1982 to 2012, and with the exception of 2020 have logged 50 to 80 flights a year since — is that four hours was a reasonable number for its time

since ~2000: airline consolidation, the overwhelming dominance of hub-and-spoke route systems (with the attendant crushes on terminal infrastructure at those hubs), and the airlines’ obsession with maximizing aircraft operating time (with the attendant schedule ramifications that are the basis for this thread) have strained the system to where — from a passenger satisfaction perspective — six hours would make a lot more sense