How to make flying with a cat easy

I’m moving overseas in August, from America to Europe. And I have a cat, she’s flown before but was very short flight roughly only an hour and a half, she did pretty good never meowed super quite( was kinda scary at some points since she is Siamese and meows all the time.) it’s a 12 hour flight, not sure how She’ll do but she’s also pretty chill. I did order a collapsible litter tray to be able to let her potty every few hours in the bathroom and I will line her carrier with pee pads just in case. Any other tips to make the flight easier for her? Thanks in advance