Hellobee Boards

Sounds like a good plan. Have you tried pouches with them yet? I would get them used to them beforehand if you can. Some LOs don't really like them or take awhile to get used to them (my LO never liked them).

Pouches (get ones that are neutral-ish colors so less stain potential)
Take a couple bananas (it sounds gross but I would bite off a piece and mush it a tiny but with my mouth and then hand it to him).
Yogurt melts? If you've done them already.
Really soft steamed carrots and peas in little Tupperware containers.

Those are all things I've done in the past on a flight and have been pretty easy and a hit.

I can't remember if your babies are old enough for puffs or Cheerios yet? Those always provided lots of distraction for us.

The boon spoon is also great for purees/yogurt on the go

Warning - both pouches and sippy/straw cups can pressurize during takeoff and will squirt everywhere with great force when you open them (I learned this the hard way with a straw cup of apple juice!)

For cups, open the lid to let out air before you open the spout/straw and give it to your LOs. For pouches, I'm not sure there's another way except to open with caution - I always used jars to avoid this concern.