Well, we have to know how many persons are going to be transported from point A to point B, and the question was about the most adequate plane to fly coast-to-coast, assuming we are talking about the US. So, in route X-Y we really have to use the available data at the time of the comparison.
Although the demand is variable, the truth is, it's the only thing we can use, and all things being equal, we need to establish a logical point of comparison.
One of the things that is most important in the decision about which plane to use is fuel consumption, as sometimes fuel represents 80% or even more of the whole operational costs.
Therefore, I atempt to calculate as accuratelly as possible, how much would a plane spend in fuel terms. The fuel flow is important, but the number of passangers and speed affect the calculation.
So, I calculated how long would the plane need to be flying (and consuming fuel) in order to complete a certain task (transport an X number of passengers).
I concluded that there are old planes that although flying much slower, have such a low fuel consumption rate, that they still would be more fuel efficient than far more modern planes.
I should know a 737 of the NEO series is from a different generation from the CL-44 Yukon, my point is, that the faster speed and confort of the 737-NEO are not apparently taken in consideration (at least as IMO they should).
It seems to be a distortion of the game.
You have people happily flying DC-8-40's and 707-420's, when noise regulations would have banned them. You have hundreds and sometimes thousands of Tupolev Tu-114, when we know that the plane was literally painfully noisy to travel in.
The situation is such, that even a 20 year old Yukon, can be used if competition and ticket prices plumet, and if you have ordered some hundreds for delivery during 20 years, far long after the plant actually have closed, you can still use brand new planes, although from an oder generation.
I agree that there are some planes that have characteristics that are inconsistent with realty, the CL-44 being one of them, the Tu-114 another and the IL-18D probably. (russian aircraft fans are going to have a stroke)
And I was joking about waiting for the CL-44 Yukon, of course …