Ok this is huge to implement, but I think it can be very interesting and it can also make the game really unique.
There should be a "charter flights" page, where you can see a list of charter flights request, eg:
LHR to RMF, every Sat from March 14th to October 1st, for 180 pax, 55,000 USD/leg. Penalty 5000000 USD.
If you accept it, you must make sure you organize the flight. The flight will not generate "standard" revenue based on LF, so it will not be affected by passenger request rules: you will just receive that particular fixed income.
What do you think?