I think that's the reality!!! Try to remember last year in our real world (2008), the fuel price ran to a crazy level. Many airlines were forced to ground their B747-400, which is already considered a modern aircraft when compared to B747-200 or DC-x or .... !
That's why in this game, I never consider to use B747-100 / 200 / 300 or other classic aircraft, except B727 (due to the shortage of A320!) But I will definitely replace those old B727 with A320 soon.