I try to keep it simple and lightweight but still pack the necessities... for me that is to start with a large purse. Then I make sure to add my iPhone and iPad (stocked with perhaps a movie and definitely a few books) and a power cable. Then other small personal necessities like hand cream, lip gloss, hand sanitizer and small bags to keep all the items organized are a must. I finally broke down and bought a travel pillow (nerd alert!) because I really don't fly "well" and would prefer to sleep... so I am hoping this eases me into some serious zzzzz's. Lastly a scarf to keep warm if need be and some sunglasses to say "don't bother me" or for a sunny locale when I land. I'll probably also add some trail mix and a few of my favorite tea bags in case I want a healthy snack on board or while waiting at the gate.
What are your carry on essentials?