What are your own essential items for carry on bags for air travel?

One scrunchie, some kind of snack, at least two books, one magazine, gum or mints (for motion sickness), a hairbrush, iPod, laptop, and some other activity (homework, a game, sudoku, etc.).

If I were going to fly this day and age I would be packing the following:
2 extra outfits and underwear
toothbrush
mints for breath
hairbrush
book
magazine
meds that you might need with doctor note
(some of the things people would normally take will not be allowed because of the latest threats and all so ask at the airport if going out of country.)
take if allowed:
deoderant
toothpaste
perfume
snack
cellphone (airlines are getting hard on this)
laptop(ask airlines first)
digital camera(ask airlines first)

Because of the threats we have had in the past it is best to ask the airlines and especially if going out of the country if certain items can be taken. If not you will have to deal without them.

Standard items- Water, small snack (granola bar/power bar variety), books, a hairtie, music, babywipes, gum (for motion sickness and to help your ears adjust to altitude), cellphone (turned off) to make travel arrangements on landing. You'll want any itinerary or reservation confirmations handy. ID, money and anything you would normally put in a purse or wallet should stay with you at all times. Tampons or pads if you are female (better safe than sorry) Also- pack a pair of clean underwear. It sounds silly but if the airline loses your checked bags you'll be grateful.

If you are traveling for business make sure any important papers or laptops go on with you for the same lost luggage purpose.

If you are traveling for pleasure keep your camera handy.

If you are flying for several hours I highly recommend a small throw and pillow- some airlines still carry their own but do you really want to trust how often they are laundered with constant trips from here to there?

Enjoy your flight!

disposable panties, tooth-brush, dry and wet tissue paper, lipstick, comb,headache pill, pen, small amount of currency where we will transit in case of emergency, small amount of currency of the country of disembarkation, small address/phone book

A book is always good, but don't buy one at the airport, because you might not like it, and then you are stuck. The nice thing about a book is that it's not electronic, it's not liquid, they don't make noise. The best thing is if you have a book you already started, so you're already interested, but you are less thean 1/4 through it. Then you read in airport, read on plane, it's nice!

Being a Flight Attendant I can tell you, that you should definitely try to lighten your load. What you carry should depend on where you are going. Always carry your passport/Id,cell phone, money and tickets.(Do not put these in the overhead compartment) Also, carry any medication you take, and instructions on how to give it in case something were to happen to you during flight. As far as stuff in case the airline loses your bag....they will provide you with a toiletry kit, with toothbrush, paste, etc. You may want to carry a change of clothes and pajamas, to get you by until they locate your bags. The airplane has water & drinks onboard. Some flights don't provide food, so you may want to pack a snack. Try to pack your carry on items in a case that rolls so you don't have to carry it all over the airport. If you like to read take a book or magazine. You don't need to take a lot because they tend to get heavy, and take up a lot of space. If you are going on a short flight or to visit relatives, you could leave off the clothes, and snack and lighten the load even more. Remeber planes are tight for space, and the more stuff you have, the more cramped you will be. P/S If you are going on a long flight or a flight at night you should difinitely take an eye mask and ear plugs. One more tip...Always put your name, address, and phone number inside all your luggage if luggage tags come off and luggage is lost, the airline will still be able to identify yours. Oh Yeah, airplanes have feminine products in the lavs so you are covered there.

I never check bags and I can fit all of this into a single roll-aboard style carry-on bag:

laptop, network cable, charger
ipod, cell phone, PDA and chargers
1 pair of shoes
clothing for however long the trip is (recently I had a week-long trip for work and had 1 skirt, 1 pair of pants, 2 shirts, a sweater, stockings, undies, socks and pajamas)
makeup, hair brush
travel-size Scrabble
2 pillowcases (I take my own when I travel)
Book or magazine

Yes, it all fits if you know how to pack it right and if you choose items that don't take a lot of space when they're folded. And yes my bag weighs a ton but it has wheels so dragging it around is still a lot more convenient than waiting at the baggage claim.