Cocomama is a standard in my bag along with the nuts and protein bars previously mentioned. It is quinoa cooked with coconut milk in a shelf stable pouch. Just need a plastic spoon.

Also individual serve PB with an apple or carrot sticks. Never been raised as a gel concern.

If available at airport, I will also grab the individual hummus & pretzel packs. At PVD I often grab a salad from Wolfgang Puck to go.