we leave off the 5 or 4, most of our flights begin with 5, historically ASA was always 4.
so since flight 5052, is call sign Comair 52.
if the flight between, CVG and OKC and CVG is 5632 and 5632, the CVG OKC is flight 632, the flight between OKC CVG is 1632, just add a "1" for the same number on a return flight.
ok?