How about a baby quilt or two that are ready to quilt when you get on the plane, and that you enjoy handquilting for the many hours it will take to get there? My other idea, since you have (UGH!) 18 hours to spend---TWICE---- is a project that maybe you've always wanted to try but never have...handpiecing or applique or maybe both. Make yourself a kit with all the pieces cut before you go. Congrats on becoming a grandma! It's a most wonderful thing to be!!!!!