It is curious.
I"m in 1969 in my World and i realize that the most profitable aircrafts are: Bac 1-11-200 and Dc-9-30.
About DC-9 X 737-100/200, the 737 consumes a lot of more fuel than the DC-9 and, in my case with Focus cities in Europe, the Range in 737 is not so useful(and also, the speed is bigger in DC-9(wich is very useful in European flights.
About the 1-11, i use him in US bases, because of the 89 seat, the big range and comparable fuel consumption with the DC-9(and a good price - 37 million x 51 million of the DC-9).
Just one big doubt i have: How many years should i let an aircraft flying in my company? About 4-5 years is the maximum time until i retire my aircrafts.
I saw some of my competitors still using Comet 4B, C and TU-104(wich are more expensive to but and to maintain - with a musch bigger fuel consume).
In my first world in AM, in the end of 2007, i realize that make a default in the fleet of my airline have been very useful, but i didn't retire my aircraft fleet so... the mainteinance costs became so higher that i started to losing money every end of month.
Best luck for all!
