Oversized definition varies some by airlines. Generally, if the sum of the length + width + height is 62" or less and weight is 50lbs or less your good.Could be a long shot but does anyone know of a case that isn't oversize baggage?
I think a big roller duffel that doesn't look like it contains a bow is an advantage over a hard case that screams hunting gear, at least around the bigger cities. The XL Cabelas Ripcord rolling duffel is 42" long and 18" wide and stuffs to about 18" high. It cost me $26 in excess baggage charges when it was under 50#s, and $28 when it weighted 59# on a recent "long" Canadian trip. Not bad, considering one extra bag would have been $100. Good luck with it!