Travel Note
You can soar in the sky to land at ACK (Nantucket's airport code) (and also Nantucket's nickname) (which you'll see on every bumper sticker, hat and shirt while you're there). But yeah, direct flights from NYC to ACK are easy - not cheap - but easy.
Travel Note
Ferry-ing is an adventure worth trying. And tissues are worth bringing if you're Talia who cries on the ferry home every. single. time. Anyway, drive yourself to Hyannis, MA, where you can park your car (for $15/day) and hop on the Hy-Line fast ferry which is a smooth-sailing sixty minutes to Nantucket!