Yes, I'd agree that powders are the best way to go. And, they do go through airport security just fine.
The last few times that I have been flying I have made muffins out of oatmeal using 5 powder packs. I put eggs in as part of the recipe and so I had mini muffins all day and a salad w/o dressing during a lay-over.
In fact, I have a day of flying to do tomorrow and my muffins are in the fridge waiting...
Now, think about this: on your way back home you'll have tons of spare room in your suitcase having eaten all your powder! I'm saying, you can do a little shopping and have some luggage space to bring stuff home. Maybe, say, some new smaller clothes or such...umm?!
Have a great trip and take care of yourself!