That is all and good if the MD-80 fills those seats, which would have to have the same price per seat for the comparison to work. The problem is that on many E-140 routes the MD-80 might only be 1/2 full, and half of those seats sold will be at cheap rates to try to cover the costs of the flight, which attempts to compete with a low cost carrier, which we just can't.

The mistake many pilots make is that you can't compare apples and oranges as they do with hub and spoke -vs- low cost carriers; -where the hub and spoke ticket prices vary greatly (first class/coach, point to point/connection, domestic/international) whereas the LCC tickets are more uniform. One connecting passenger on a E-140 can pay for the whole flight and part of the next one to support the frequency, which attracted the international customer in the first place. Without frequency to the hub, and connection to those smaller cities in general, you might not fill that international flight. That is where market share comes in.

So the EMB-140 might have more costs per seat mile, but it's revenue per seat mile is much higher on average because a larger percentage of the aircraft is higher priced tickets. And without frequency those high priced international first class tickets would go to the competition.

Costs per available seat mile is only part of the equation for hub and spoke. LCCs have a much easer equation, where lowest Costs per seat mile are much more critical. I suspect that is where Boyd goes wrong so consistently.