Interesting numbers.

While unable to obtain, a true cost would be based on efficiencies/inefficiencies of the certain models. For example, the MD-80's are probably not as efficient as a 777 which isn't really reflected in the numbers.

All in all though, I think $0.13 sounds like a decent gauge although its a straight average and not weighted to the number of aircraft actually available of each type.

Anyway, would be interesting to compare to other carriers.