If you’re a vegan, it’s a bad idea to rely on airline food on long flights.
How to keep food cold when you can’t take ice through security.
I travel with a small, soft cooler bag. I don’t want the extra weight of ice packs so I just freeze water in a soda bottle to use as an icepack. Since I can’t take this through security, I dump it out. Once I’m through security, I ask for some ice at a Starbucks or similar. I keep a plastic bag handy and ask them to put some ice in the bag. I’ve never been refused. Staff have always seemed happy to help. I also tend to carry the cooler bag inside a plastic shopping bag in case the ice starts to melt and drips.