I have long since given up trying to plan sleep on planes. My body clock spends it's time being entirely confused unless I get a week or three in Sydney when I can revert to normality. So for me, if I'm awake I eat. If I'm asleep then I don't. Sometimes that means eating constantly and sometimes it means I will have snagged an UuA to F and get on and don't interact with anybody until I wake up and have a coffee.