So I called SW airlines and asked them how I could bring a cake with me on my flight from AZ to WA. They told me as long as I can fit it under the seat in front of me it wouldn't be a problem. Obviously this will NOT work. Has any one flown with one of their cakes before? What do I need to do. Also, I am flying Stand-By, so that might be a factor if I don't make it onto a non-stop flight.

..moving to Cake Decorating.

I don't know how big your cake is, but I traveled just fine with a 12x6 inch cake box. There was plenty of room under the seat in front of me.

You may want to double check the TSA website about your cake. With the most recent terrorist attempts, you might encounter more scrutiny. In my case, I had to check it through security like I would with any typical carry-on bag through the scanner.

What other folks have done is ship their plain cakes and travel with the decorating items. The latter could also be an issue if your fondant is mistaken for plastic explosives. Another CCer actually had this happen!

Oh yeah, I also recall some other folks buying another plane seat if their cakes were pretty big.

Not sure about SW but Delta told me that I could carry it to the gate and then they could put it in the front storage compartment and when I arrived they would give it back to me at the arrival gate - like they do with strollers or Wheelchairs.
I contacted home land security about bring a cake in the airport. They said it was okay but that you could be subjected to a more detailed screening.
Called and got this info so I could bring a cake from a class I was taking back home. Backed out because didn't want the possible hassel with security.
Good Luck.