Porridge!!
I used to suffer bad sickness in small boats, was recommended to eat something filling but bland like porridge. It worked a treat to stop seasickness, so when I started flying I tried the porridge right from the start and never had a problem. When I started overnight trips and couldn't get porridge in the morning I almost needed the bag once or twice but now I'm fine. Don't know whether this was physical or psychological but the porridge worked for me.