I would love to make a birthday cake for a friend who lives in Utah. Any suggestions on how to travel (if possible) with the cake on an airplane?

It depends on how big? tiered? of a cake you are trying to travel with you could always back the cake wrap in plastic wrap put in tupperware box and carry on and decorate it when you get to Utah. But traveling with a decorated cake could be a disaster. I live in Northern Utah and had to travel to Wendover with a wedding cake. we baked the cakes, Iced and covered in fondant and put them in air tight tupperware containers with a non slip bottom and then stacked and decorated in the conference room of the hotel where the reception was to be held and that was a big pain in the butt. I would recommend if you could to come a day or two early and do it here for them. Good luck with whatever you decide.