I've flown 3 times over the last year on hunting trips. The most recent one was only about a month ago. You need to have your rifle in a lockable, hard-sided, guncase. You need to declare it to the attendant when you check in. He/She will check that it is unloaded and make you sign a declaration. Then you go through security and lock the case back up after they look at it. Make sure all your ammo, and anything sharp is in your baggage. Make sure ammo is in an ORIGINAL FACTORY box. They are very particular about this. Even if you reload, put your ammo in a factory box.
Load your optics, license/tags and a set of hunting clothes in your carry on pack. Wear your boots. That way if the airline loses your baggage, you can buy more ammo at a local store and still be able to hunt. This saved my buddy's hunt after flying into Casper.
Take a 60qt cooler with you. Check it as baggage. On the way home you can pack your meat in there and duct tape the cooler up. You will have to tape it after it goes through security. Meat will stay frozen for a couple days if you have a good cooler and keep it taped up. A boned out deer will fit in a 60qt cooler. You can insulate the meat with clothing if you'd like. Or pack 5lbs of dry ice in the cooler if you are real concerned. You are only allowed 5lbs of dry ice per person but that is plenty. Make sure you open the drain plug on your cooler if you use dry ice as the expansion created by the plane's altitude, and the gas of the ice evaporating, will blow the lid off, or split the sides, of your cooler if air cannot escape. You might get charged for extra baggage and/or for it being overweight, but it is still cheaper than shipping meat.
Now if you kill a trophy, IMO, it is best left with a local taxidermist who can hanlde it for you. It is not worth the airline baggage clowns breaking your horns or losing the trophy of a lifetime. The extra $100-200 that the taxidermist might charge for crating and shipping your trophy is well worth it. Of course you could buy another plane ticket a put the horns in the seat next to you. I actually know someone who did this.
Good luck and have fun!