Personally, the little bird shouldn't be based on rank.
Another option would be a higher up (or a constable if needed due to people's real lives, which come first) that is authorized to "certify" APD constables or higher for flight. This of course would require more stringent regulations when it comes to air patrols being that it could very well be a constable flying around, but with more stringent regulations comes higher punishments. Someone messes up when flying, give them a warning. They do it again? Ground them for a few days. They just don't get it and screw up a third time, revoke their flight privileges and have them sell their chopper. (Yes this is a loss in money, maybe they shouldn't have f***ed up THREE times)
It could work where an "instructor" who is whatever rank (again, real lives) is tasked with heading up the Airial Unit for APD. Someone wants to join up, they apply. If they're accepted, they go out with an instructor who interviews them in flight (or before, whatever) and gives them control of the bird. At that point, its up to the applicant to perform various actions such as touch and goes, handling tests, pursuit, etc. Point is, not everyone can fly (as mentioned by Jamal) and those who can might not be able to. Birds should be a privilege granted by certification, not a right based on rank.
PS: I think this is what you were looking for Thomas.