To mail antlers you will need to cut the skull plate... last time I did one I bored a large hole up through the inside of the skull plate and bedded a waxed piece of allthread in epoxy. Then I removed the allthread and cut the antler off rather than splitting the skull. When reassembled a little bit of epoxy replaced the bone removed by the saw and the cast epoxy threads makes everything line up correctly.
Flying home with your meat is usually easiest, though not real cheap these days. Some airlines allow first class to check extra bags for free... if you have to pay extra for bags it might make sense to go first class for a bit extra?
