I travel incredibly lightly, even with babies/toddlers/tinies on long haul flights. My tricks for anyone over 6 months are:
Two bottles, just rinse with a bit of hot water when necessary. They survive. Roll up disposable bottle tucked away in case of disaster. I've even used Fruit Shoot bottles for formula when stuck. The world didn't end.
Break all the rules on formula - take 7 scoops per feed in a container with compartments, add 7 fl oz hot water or Evian as required. Shake. Again, they survive, amazingly.
Take nappies for 24 hours in case we're stranded, full pack wipes.
Take 2 day outfits as well as 2 babygros that could just about pass for daywear.
Big carrier bag tucked away in case of big mess.
Packet of raisins, one or two Farley's rusks.
Soap leaves and smallest size travel towel.
Spare t-shirt for me.
Extra blanket for on the plane.
That's about all I take. Food wise I just feed them bits of whatever they have on the plane, than I am eating (I chew it up for them, if necessary).