Similar Dissertation
Sounds like your project is similar to my final year dissertation. However, yours is a little more extensive in terms of routings.
My advice will be to check the airport's website and see if you can find fix charges for services such as ground crew and handling. I know Oxford have theirs on their website.
Then contact MRO organisations/lessors for maintenance/crew price. You will find that a lot of company will be reluctant to share the cost of charges. Can't blame them really as they are a business at the end of the day.
It will be wise to broaden your horizon in terms of finding the cost of such service.