I understand what you are saying about "buying power" as Joel says a similar trip is just a bit more than your estimate.  (Although I should say that a plane ride vs a rail journey isn't exactly a "similar" trip when you consider what you are getting in terms of quality of trip vs. lenght).  

BUT, I am wondering if there is a distinction of some sort between "buying power" and "earning power."  For example, if a person earned $40 a week in 1914 would that person earn $900 a week in today's dollars? I have a hunch that it may have been easier to come up with $40 in 1914 than it is to find $900 today. Things like inflation and amortization, etc are all very confusing to me.