This has been referenced to an existing Topic:- New Features: Name schedules, not aircraft, Aircraft pools (Read 1339 times) which isn't a clear request for anything in particular. I hope this suggestion does have some merit from the players and the programmers view.
I would like to see a 'support aircraft' facility allowing a nominated replacement to be provided to make the flights for an aircraft in C or D checks. One (older?) aircraft being assigned to all the rest of that type at that airport.
Whether a B737 could cover for a B747 is debateable but if the flight time and turnaround time are virtually the same then at least the route is provided for, even if not fully.
The support aircraft in RW would be A and B serviced on an hours flown basis. Long term perhaps any aircraft that has flown less than 40? hours since last A service can pass for that week.