Personally if I was Mississippi I would just bring cowbells and ring them every time MSU is on offense. Bringing air horns is pretty damn gay and much more annoying than a cowbell.
Plenty of UM rooters in both (probably a few more north of Schoona). Hell, even had one that grew up in BC & lived in Vardaman. Don't know if he knew how to get to Oxford, but he had this huge UM logo painted all the way down both sides of his Chevy Luv (or insert comparable small truck).