I was fasting for surgery on the day of my plane ride, and it's only a little over an hour flight from Vegas but if I were you I would check in and then sit and have a canned slimfast right before going through security and then buy yourself some water and a small salad (most airports have a subway) or even that apple/walnut dish that McDonalds has IF you need a snack on the flight... I know it's tough we had a morning flight and the entire terminal smelled like those damn Cinnabons, my mouth was watering...
But, this is where you start learning that you need to have your head in the right place and make better choices about food before ever getting your band, luckily it provides a lot of the will power but you have to do the rest (and it sounds like you are already doing wonderfully)!