Take off is the best bit
Just lie back, take deep breaths, when you hear your ears pop (when the plane banks) swallow hard, don't eat anything like sour sweets or that (personal experience suggests it'll give you acid reflux), turn the zircon above you on to keep cool. If you need to ask the staff if you can have a blanket, eye mask, lay off caffeine and stick to water/squash, it's pretty steady and the safest way to travel but if you explain to someone (family or staff) that you're anxious they'll do all they can to relax you.
I get awful motion sickness but I'm not bad on planes at all. If I can do it you can
good luck and enjoy the holiday, NYC you lucky duck