Another person who's precious snowflake has an allergy...booo hooo. I'm sorry, but I won't let my eating be deterred because junior can't suck it up and deal with his allergies.

Grapes and apples, cut up as necessary (and not just for the allergic toddler!). Yes, you might have to toss the surplus before you get off the plane, but that's ok.

If you want to keep things cool bring a small cooler bag and some ziplocks. Then get ice once you go through security (I've had places that serve fountain drinks give me ice for free). But from experience I recommend double bagging the ice! . On that long flight you could ask the flight attendant for ice refills on the way. Won't be super cold but good enough for sandwiches etc